From seminars-announce.astro-at-su.se at lists.su.se Mon Jan 24 13:48:21 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 24 Jan 2022 12:48:21 +0000 Subject: [Astronomy seminar] Astronomy seminar on January 28 Message-ID: Hello, On Friday the 28th we have the next astronomy seminar with Laura Kreidberg (Max Planck Institute) speaking at 10:30 via Zoom. Planets are Places: Characterization of Other Worlds in the 2020s and Beyond The past 25 years have revealed a diversity of exoplanets far beyond what was imagined from the limited sample in the Solar System. With new and upcoming observing facilities and a rapidly growing number of nearby planets, we are poised to bring this diversity into focus, with detailed follow-up characterization of the planets' atmospheres. In this talk, I will discuss three frontier questions in exoplanet atmosphere studies: (1) what can we learn about the planets' origins and evolution based on their present-day atmospheres? (2) how are the climate and clouds of exoplanets shaped by their extreme irradiation environments? and (3) under what circumstances do terrestrial exoplanets retain atmospheres? Finally, I will conclude with my outlook on the search for biosignatures in the atmospheres of potentially inhabited planets. If anyone is interested in chatting with the speaker, we can leave the zoom call opened after the seminar. Cheers, Chris and Carolina ----------------------------------------------------------------------------------------------------------------------- Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Laura Kreidberg Time: Jan 28, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66310610960?pwd=SitJZGI3ZUl5b3ZzWkNVZEZ1clpmdz09 Meeting ID: 663 1061 0960 Passcode: 621431 One tap mobile +46850520017,,66310610960# Sweden +46850539728,,66310610960# Sweden Dial by your location +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +46 8 5016 3827 Sweden +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden Meeting ID: 663 1061 0960 Find your local number: https://stockholmuniversity.zoom.us/u/cd6cZRo2T3 Join by SIP 66310610960 at 109.105.112.236 66310610960 at 109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 663 1061 0960 Passcode: 621431 Join by Skype for Business https://stockholmuniversity.zoom.us/skype/66310610960 --------------------------------------------------------------------------------------------------------------- Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Jan 28 09:20:55 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 28 Jan 2022 08:20:55 +0000 Subject: [Astronomy seminar] Reminder: Astronomy seminar on January 28 In-Reply-To: References: Message-ID: On Friday the 28th we have the next astronomy seminar with Laura Kreidberg (Max Planck Institute) speaking at 10:30 via Zoom. Planets are Places: Characterization of Other Worlds in the 2020s and Beyond The past 25 years have revealed a diversity of exoplanets far beyond what was imagined from the limited sample in the Solar System. With new and upcoming observing facilities and a rapidly growing number of nearby planets, we are poised to bring this diversity into focus, with detailed follow-up characterization of the planets' atmospheres. In this talk, I will discuss three frontier questions in exoplanet atmosphere studies: (1) what can we learn about the planets' origins and evolution based on their present-day atmospheres? (2) how are the climate and clouds of exoplanets shaped by their extreme irradiation environments? and (3) under what circumstances do terrestrial exoplanets retain atmospheres? Finally, I will conclude with my outlook on the search for biosignatures in the atmospheres of potentially inhabited planets. If anyone is interested in chatting with the speaker, we can leave the zoom call opened after the seminar. Cheers, Chris and Carolina ----------------------------------------------------------------------------------------------------------------------- Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Laura Kreidberg Time: Jan 28, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66310610960?pwd=SitJZGI3ZUl5b3ZzWkNVZEZ1clpmdz09 Meeting ID: 663 1061 0960 Passcode: 621431 One tap mobile +46850520017,,66310610960# Sweden +46850539728,,66310610960# Sweden Dial by your location +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +46 8 5016 3827 Sweden +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden Meeting ID: 663 1061 0960 Find your local number: https://stockholmuniversity.zoom.us/u/cd6cZRo2T3 Join by SIP 66310610960 at 109.105.112.236 66310610960 at 109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 663 1061 0960 Passcode: 621431 Join by Skype for Business https://stockholmuniversity.zoom.us/skype/66310610960 --------------------------------------------------------------------------------------------------------------- Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Tue Feb 1 10:03:40 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Tue, 1 Feb 2022 10:03:40 +0100 Subject: [Astronomy seminar] Astronomy Department Seminar - February 4th Dan Perley Message-ID: On Friday the 4th at 10:30 we have our second seminar of the year with Dan Perley (Liverpool John Moores University) speaking via Zoom. *A Complete Survey of the Catastrophic Universe* While it looks static to the naked eye, the night sky is filled with activity: a star explodes somewhere in the observable universe once every second.  The vast majority of these explosions go unheralded, but a new generation of synoptic optical surveys are finally enabling us to systematically chart the entire parameter space of these dramatic endpoints of stellar evolution. I will describe how we are using the Zwicky Transient Facility to investigate this "zoo" of cosmic explosions. I will first present new measurements of the rates, luminosity functions, and demographics of a variety of well-established supernova types and illustrate how these observations are providing new insights into the connection between the lives and deaths of their massive stellar progenitors.  Then, moving to the extremes of stellar evolution I will summarize our discoveries of the rarest and most energetic explosions: off-axis gamma-ray bursts, "dirty" fireballs from moderately-relativistic jets, direct-collapse events, and kilonovae. We are trying something new this year with leaving the Zoom call open after the formal hour of the seminar is up to allow the speaker, if they wish, to chat informally with anyone who is interested. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Dan Perley Time: Feb 4, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66820045606?pwd=em5rS2ptMWIwVXVvNkVZL002NWxwZz09 Meeting ID: 668 2004 5606 Passcode: NSenCIPabo -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Feb 4 09:59:43 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 4 Feb 2022 09:59:43 +0100 Subject: [Astronomy seminar] Astronomy Department Seminar - February 4th Dan Perley In-Reply-To: <825b2366-3605-6e28-ad02-e1b718e2af84@astro.su.se> References: <825b2366-3605-6e28-ad02-e1b718e2af84@astro.su.se> Message-ID: Reminder, Dan's seminar will be in 30 min! C On 01/02/2022 10:03, Chris Usher wrote: > > On Friday the 4th at 10:30 we have our second seminar of the year with > Dan Perley (Liverpool John Moores University) speaking via Zoom. > > *A Complete Survey of the Catastrophic Universe* > > While it looks static to the naked eye, the night sky is filled with > activity: a star explodes somewhere in the observable universe once > every second.  The vast majority of these explosions go unheralded, > but a new generation of synoptic optical surveys are finally enabling > us to systematically chart the entire parameter space of these > dramatic endpoints of stellar evolution.  I will describe how we are > using the Zwicky Transient Facility to investigate this "zoo" of > cosmic explosions. I will first present new measurements of the rates, > luminosity functions, and demographics of a variety of > well-established supernova types and illustrate how these observations > are providing new insights into the connection between the lives and > deaths of their massive stellar progenitors.  Then, moving to the > extremes of stellar evolution I will summarize our discoveries of the > rarest and most energetic explosions: off-axis gamma-ray bursts, > "dirty" fireballs from moderately-relativistic jets, direct-collapse > events, and kilonovae. > > We are trying something new this year with leaving the Zoom call open > after the formal hour of the seminar is up to allow the speaker, if > they wish, to chat informally with anyone who is interested. > > Thanks > > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar - Dan Perley > Time: Feb 4, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/66820045606?pwd=em5rS2ptMWIwVXVvNkVZL002NWxwZz09 > > > Meeting ID: 668 2004 5606 > Passcode: NSenCIPabo > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Feb 7 10:15:23 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 7 Feb 2022 09:15:23 +0000 Subject: [Astronomy seminar] Astronomy Seminar 11/02 Message-ID: On Friday the 11th we have the next astronomy seminar with Anke Arentsen (Observatoire Astronomique de Strasbourg) speaking at 10:30 via Zoom. Galactic Archaeology with the oldest stars in the Milky Way The oldest, most metal-poor stars we find in the Milky Way today were born in pristine environments in the early Universe. They contain unique clues about the First Stars and the early formation and evolution of our Galaxy. Most metal-poor stars are found in the Galactic halo, but the central halo overlapping with the Galactic bulge has often been avoided — it is challenging to identify metal-poor stars in this dusty, crowded area of the sky. In this talk, I will introduce the Pristine Inner Galaxy Survey (PIGS) which has reached unprecedented efficiency in finding very metal-poor stars in the Galactic bulge region. I will present recent PIGS results on the chemistry and the kinematics the metal-poor inner Galaxy, and discuss what they can teach us about this ancient component of the Milky Way. Of particular interest in Galactic Archaeology are the carbon-enhanced metal-poor (CEMP) stars, which are thought to be probes of the First Stars, early chemical evolution and binary interactions. I will also present some recent results on these CEMP stars. If anyone is interested in chatting with the speaker, we can leave the zoom call opened after the seminar. Cheers, Chris and Carolina --------------------------------------------------------------------------------------------- Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Anke Arentsen Time: Feb 11, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66310610960?pwd=SitJZGI3ZUl5b3ZzWkNVZEZ1clpmdz09 Meeting ID: 663 1061 0960 Passcode: 621431 One tap mobile +46850520017,,66310610960# Sweden +46850539728,,66310610960# Sweden Dial by your location +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +46 8 5016 3827 Sweden +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden Meeting ID: 663 1061 0960 Find your local number: https://stockholmuniversity.zoom.us/u/cd6cZRo2T3 Join by SIP 66310610960 at 109.105.112.236 66310610960 at 109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 663 1061 0960 Passcode: 621431 Join by Skype for Business https://stockholmuniversity.zoom.us/skype/66310610960 ------------------------------------------------------------------------------------------ Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Feb 11 09:55:43 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 11 Feb 2022 08:55:43 +0000 Subject: [Astronomy seminar] Reminder: Astronomy Seminar 11/02 In-Reply-To: <49980260892e49638c9c4b70774351bd@astro.su.se> References: <49980260892e49638c9c4b70774351bd@astro.su.se> Message-ID: On Friday the 11th we have the next astronomy seminar with Anke Arentsen (Observatoire Astronomique de Strasbourg) speaking at 10:30 via Zoom. Galactic Archaeology with the oldest stars in the Milky Way The oldest, most metal-poor stars we find in the Milky Way today were born in pristine environments in the early Universe. They contain unique clues about the First Stars and the early formation and evolution of our Galaxy. Most metal-poor stars are found in the Galactic halo, but the central halo overlapping with the Galactic bulge has often been avoided — it is challenging to identify metal-poor stars in this dusty, crowded area of the sky. In this talk, I will introduce the Pristine Inner Galaxy Survey (PIGS) which has reached unprecedented efficiency in finding very metal-poor stars in the Galactic bulge region. I will present recent PIGS results on the chemistry and the kinematics the metal-poor inner Galaxy, and discuss what they can teach us about this ancient component of the Milky Way. Of particular interest in Galactic Archaeology are the carbon-enhanced metal-poor (CEMP) stars, which are thought to be probes of the First Stars, early chemical evolution and binary interactions. I will also present some recent results on these CEMP stars. If anyone is interested in chatting with the speaker, we can leave the zoom call opened after the seminar. Cheers, Chris and Carolina --------------------------------------------------------------------------------------------- Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Anke Arentsen Time: Feb 11, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66310610960?pwd=SitJZGI3ZUl5b3ZzWkNVZEZ1clpmdz09 Meeting ID: 663 1061 0960 Passcode: 621431 One tap mobile +46850520017,,66310610960# Sweden +46850539728,,66310610960# Sweden Dial by your location +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +46 8 5016 3827 Sweden +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden Meeting ID: 663 1061 0960 Find your local number: https://stockholmuniversity.zoom.us/u/cd6cZRo2T3 Join by SIP 66310610960 at 109.105.112.236 66310610960 at 109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 663 1061 0960 Passcode: 621431 Join by Skype for Business https://stockholmuniversity.zoom.us/skype/66310610960 ------------------------------------------------------------------------------------------ Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Feb 14 10:42:03 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 14 Feb 2022 09:42:03 +0000 Subject: [Astronomy seminar] Astronomy seminar on 18/11 Message-ID: On Friday the 18th we have the next astronomy seminar with Lorenzo Nativi (Stockholm University) speaking at 10:30 via Zoom. (Please, join the call before 10:30!) Investigating the jet-ejecta interaction in neutron star mergers GW170817 represented the first detection of a binary neutron star merger, and the coalescence of the two neutron stars was followed by both the ejection of neutron-rich material and the launch of a relativistic jet. These two dynamical components, mildly-relativistic ejecta, and ultra-relativistic outflow, were detected independently: the first one powered a "macronova" (or "kilonova"), a thermal transient powered by the radioactive decay of the freshly synthesized r-process nuclei. The jet instead powered a short GRB consisting of an early gamma-ray signal followed by a multi-wavelength afterglow. The presence of a jet successfully breaking out from the ejecta was additionally confirmed by the detection of superluminal motion. These two components were detected and modelled independently, but they interact before becoming visible, and this might have left an imprint on the detected signals. I will discuss the results of the 3D special-relativistic simulations used to investigate the consequences of a jet propagating through a realistic environment, created by a neutrino-driven wind around the central remnant. I will show how a jet can "punch-away" a fraction of high-opacity material at early times, before the brightening of the macronova, and how this is going to impact the observed signal. Then I will show what happens in the other direction i.e., how the ejecta impact the jet. I will show that the emerging jets are mostly shaped by their interaction with the surrounding environment and their eventual initial structures only plays a minor role in the final outcome. Moreover, turbulent motions arising during the interaction produce inhomogeneities in the jet profile when observed face-on. These inhomogeneities impact the peak afterglow flux, and the inferred kinetic energy of a single jet from different observers can cover a fraction about 1/3 of the observed short GRB population. If anyone is interested in chatting with the speaker, we can leave the zoom call opened after the seminar. Cheers, Chris and Carolina --------------------------------------------------------------------------------------------- Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Lorenzo Nativi Time: Feb 18, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66310610960?pwd=SitJZGI3ZUl5b3ZzWkNVZEZ1clpmdz09 Meeting ID: 663 1061 0960 Passcode: 621431 One tap mobile +46850520017,,66310610960# Sweden +46850539728,,66310610960# Sweden Dial by your location +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +46 8 5016 3827 Sweden +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden Meeting ID: 663 1061 0960 Find your local number: https://stockholmuniversity.zoom.us/u/cd6cZRo2T3 Join by SIP 66310610960 at 109.105.112.236 66310610960 at 109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 663 1061 0960 Passcode: 621431 Join by Skype for Business https://stockholmuniversity.zoom.us/skype/66310610960 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Feb 18 08:56:31 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 18 Feb 2022 07:56:31 +0000 Subject: [Astronomy seminar] Reminder: Astronomy seminar on 18/11 In-Reply-To: References: Message-ID: On Friday the 18th we have the next astronomy seminar with Lorenzo Nativi (Stockholm University) speaking at 10:30 via Zoom. (Please, join the call before 10:30!) Investigating the jet-ejecta interaction in neutron star mergers GW170817 represented the first detection of a binary neutron star merger, and the coalescence of the two neutron stars was followed by both the ejection of neutron-rich material and the launch of a relativistic jet. These two dynamical components, mildly-relativistic ejecta, and ultra-relativistic outflow, were detected independently: the first one powered a "macronova" (or "kilonova"), a thermal transient powered by the radioactive decay of the freshly synthesized r-process nuclei. The jet instead powered a short GRB consisting of an early gamma-ray signal followed by a multi-wavelength afterglow. The presence of a jet successfully breaking out from the ejecta was additionally confirmed by the detection of superluminal motion. These two components were detected and modelled independently, but they interact before becoming visible, and this might have left an imprint on the detected signals. I will discuss the results of the 3D special-relativistic simulations used to investigate the consequences of a jet propagating through a realistic environment, created by a neutrino-driven wind around the central remnant. I will show how a jet can "punch-away" a fraction of high-opacity material at early times, before the brightening of the macronova, and how this is going to impact the observed signal. Then I will show what happens in the other direction i.e., how the ejecta impact the jet. I will show that the emerging jets are mostly shaped by their interaction with the surrounding environment and their eventual initial structures only plays a minor role in the final outcome. Moreover, turbulent motions arising during the interaction produce inhomogeneities in the jet profile when observed face-on. These inhomogeneities impact the peak afterglow flux, and the inferred kinetic energy of a single jet from different observers can cover a fraction about 1/3 of the observed short GRB population. If anyone is interested in chatting with the speaker, we can leave the zoom call opened after the seminar. Cheers, Chris and Carolina --------------------------------------------------------------------------------------------- Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Lorenzo Nativi Time: Feb 18, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66310610960?pwd=SitJZGI3ZUl5b3ZzWkNVZEZ1clpmdz09 Meeting ID: 663 1061 0960 Passcode: 621431 One tap mobile +46850520017,,66310610960# Sweden +46850539728,,66310610960# Sweden Dial by your location +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +46 8 5016 3827 Sweden +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden Meeting ID: 663 1061 0960 Find your local number: https://stockholmuniversity.zoom.us/u/cd6cZRo2T3 Join by SIP 66310610960 at 109.105.112.236 66310610960 at 109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 663 1061 0960 Passcode: 621431 Join by Skype for Business https://stockholmuniversity.zoom.us/skype/66310610960 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Feb 21 11:28:23 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 21 Feb 2022 11:28:23 +0100 Subject: [Astronomy seminar] Astronomy Department Seminar - February 25th Carlos Gomez Guijarro Message-ID: On Friday the 25th at 10:30 we have our next seminar with Carlos Gomez Guijarro (CEA) speaking via Zoom. *Understanding the role of compact star formation in galaxy evolution* Massive elliptical galaxies in the local universe appear to have their high-redshift analogues in the form of extremely compact quiescent galaxies. Therefore, it seems that compact star formation appears to play a pivotal role in the evolutionary pathways of massive galaxies across cosmic history. However, there are fundamental unresolved questions debated in the literature: How systematic is compact star formation in star-forming galaxies at high redshift? What is its role in the broader picture of the scaling relations in galaxy evolution? I will present the latest results of the GOODS-ALMA survey, a 1.1mm ALMA survey aimed to tackle these questions. Compact star formation appears to be the norm in massive star-forming galaxies at high redshift and sizes as extended as typical star-forming stellar disks are rare. It unveils as a physical driver of the behaviour of massive star-forming galaxies in the scaling relations. The new findings suggest that compact star formation is fundamental in keeping galaxies as star forming systems even when their gas to fuel star formation is very low and they are presumably on their way to quiescence. We are trying something new this year with leaving the Zoom call open after the formal hour of the seminar is up to allow the speaker, if they wish, to chat informally with anyone who is interested. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar Time: Feb 25, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/68834937137?pwd=VHFLT09YWVNrSldxMlM0K3RiTkRkUT09 Meeting ID: 688 3493 7137 Passcode: ErtHBuCTyp -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Feb 25 10:01:56 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 25 Feb 2022 10:01:56 +0100 Subject: [Astronomy seminar] Astronomy Department Seminar - February 25th Carlos Gomez Guijarro In-Reply-To: <0662d8bc-20b4-5860-1d5a-efca26fe7a9c@astro.su.se> References: <0662d8bc-20b4-5860-1d5a-efca26fe7a9c@astro.su.se> Message-ID: Reminder of Carlos's seminar in half an hour C On 21/02/2022 11:28, Chris Usher wrote: > On Friday the 25th at 10:30 we have our next seminar with Carlos Gomez > Guijarro (CEA) speaking via Zoom. > > *Understanding the role of compact star formation in galaxy evolution* > > Massive elliptical galaxies in the local universe appear to have their > high-redshift analogues in the form of extremely compact quiescent > galaxies. Therefore, it seems that compact star formation appears to > play a pivotal role in the evolutionary pathways of massive galaxies > across cosmic history. However, there are fundamental unresolved > questions debated in the literature: How systematic is compact star > formation in star-forming galaxies at high redshift? What is its role > in the broader picture of the scaling relations in galaxy evolution? I > will present the latest results of the GOODS-ALMA survey, a 1.1mm ALMA > survey aimed to tackle these questions. Compact star formation appears > to be the norm in massive star-forming galaxies at high redshift and > sizes as extended as typical star-forming stellar disks are rare. It > unveils as a physical driver of the behaviour of massive star-forming > galaxies in the scaling relations. The new findings suggest that > compact star formation is fundamental in keeping galaxies as star > forming systems even when their gas to fuel star formation is very low > and they are presumably on their way to quiescence. > > We are trying something new this year with leaving the Zoom call open > after the formal hour of the seminar is up to allow the speaker, if > they wish, to chat informally with anyone who is interested. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar > Time: Feb 25, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/68834937137?pwd=VHFLT09YWVNrSldxMlM0K3RiTkRkUT09 > > > Meeting ID: 688 3493 7137 > Passcode: ErtHBuCTyp > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Mar 7 09:08:42 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 7 Mar 2022 08:08:42 +0000 Subject: [Astronomy seminar] Astronomy Seminar 11/03 Message-ID: On Friday 11/03 we have the next astronomy seminar with Jon Sundqvist (KU Leuven) speaking at 10:30 via Zoom. (Please, join the call before 10:30!) Radiation-Hydrodynamics at the Edge: The Lives and Deaths of the Most Massive Stars in our Universe In many astrophysical situations radiation plays a key role for the dynamics of the system (AGN accretion disks and outflows, supernovae, the first stars, etc.). After first highlighting some quite general issues when dealing with such radiation-hydrodynamic (RHD) flows, this talk zooms in on luminous stars with masses many times that of our Sun. We will show how strong radiation forces there lead to highly structured atmospheres as well as powerful stellar outflows, and how such winds critically shape the violent life-cycles of these stars, all the way from their formation to their death. A few recent research-results from our group that will be discussed involve: i) how new blue-star wind models may call for a revision of the ‘standard’ formation-channel for classical Wolf-Rayet (WR) stars (as well as have consequences for formation of high-mass stellar black holes); ii) how new red-star mass loss models may tentatively explain some observed properties of Type II-P/L supernovae, and iii) how our first (and brand new) 3D-RHD models of massive helium-stars lead to a natural transition between WR stars and the hot, stripped sub-dwarfs believed to be the products of binary evolution. And indeed, we highlight how these results have all (more or less) been derived from the same overarching research question: “how to get blown away by starlight?” If anyone is interested in chatting with the speaker, we can leave the zoom call opened after the seminar. Cheers, Chris and Carolina ----------------------------------------------------------------------------------------------- Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Jon Sundqvist Time: Mar 11, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66310610960?pwd=SitJZGI3ZUl5b3ZzWkNVZEZ1clpmdz09 Meeting ID: 663 1061 0960 Passcode: 621431 One tap mobile +46850520017,,66310610960# Sweden +46850539728,,66310610960# Sweden Dial by your location +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +46 8 5016 3827 Sweden +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden Meeting ID: 663 1061 0960 Find your local number: https://stockholmuniversity.zoom.us/u/cd6cZRo2T3 Join by SIP 66310610960 at 109.105.112.236 66310610960 at 109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 663 1061 0960 Passcode: 621431 Join by Skype for Business https://stockholmuniversity.zoom.us/skype/66310610960 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Mar 11 08:54:00 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 11 Mar 2022 07:54:00 +0000 Subject: [Astronomy seminar] Reminder: Astronomy Seminar 11/03 In-Reply-To: <685bd5fcaea644ae82c0b37b825a97a2@astro.su.se> References: <685bd5fcaea644ae82c0b37b825a97a2@astro.su.se> Message-ID: On Friday 11/03 we have the next astronomy seminar with Jon Sundqvist (KU Leuven) speaking at 10:30 via Zoom. (Please, join the call before 10:30!) Radiation-Hydrodynamics at the Edge: The Lives and Deaths of the Most Massive Stars in our Universe In many astrophysical situations radiation plays a key role for the dynamics of the system (AGN accretion disks and outflows, supernovae, the first stars, etc.). After first highlighting some quite general issues when dealing with such radiation-hydrodynamic (RHD) flows, this talk zooms in on luminous stars with masses many times that of our Sun. We will show how strong radiation forces there lead to highly structured atmospheres as well as powerful stellar outflows, and how such winds critically shape the violent life-cycles of these stars, all the way from their formation to their death. A few recent research-results from our group that will be discussed involve: i) how new blue-star wind models may call for a revision of the ‘standard’ formation-channel for classical Wolf-Rayet (WR) stars (as well as have consequences for formation of high-mass stellar black holes); ii) how new red-star mass loss models may tentatively explain some observed properties of Type II-P/L supernovae, and iii) how our first (and brand new) 3D-RHD models of massive helium-stars lead to a natural transition between WR stars and the hot, stripped sub-dwarfs believed to be the products of binary evolution. And indeed, we highlight how these results have all (more or less) been derived from the same overarching research question: “how to get blown away by starlight?” If anyone is interested in chatting with the speaker, we can leave the zoom call on after the seminar. Cheers, Chris and Carolina ----------------------------------------------------------------------------------------------- Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Jon Sundqvist Time: Mar 11, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66310610960?pwd=SitJZGI3ZUl5b3ZzWkNVZEZ1clpmdz09 Meeting ID: 663 1061 0960 Passcode: 621431 One tap mobile +46850520017,,66310610960# Sweden +46850539728,,66310610960# Sweden Dial by your location +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +46 8 5016 3827 Sweden +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden Meeting ID: 663 1061 0960 Find your local number: https://stockholmuniversity.zoom.us/u/cd6cZRo2T3 Join by SIP 66310610960 at 109.105.112.236 66310610960 at 109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 663 1061 0960 Passcode: 621431 Join by Skype for Business https://stockholmuniversity.zoom.us/skype/66310610960 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Mar 14 13:31:47 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 14 Mar 2022 13:31:47 +0100 Subject: [Astronomy seminar] Astronomy Department Seminar - March 14th David Sobral Message-ID: On Friday, March 18th at 10:30 we have our next seminar with David Sobral (Lancaster) speaking via Zoom *Resolving the formation and evolution of primeval galaxies: from re-ionisation to cosmic noon* I will present new results that reveal the nature and evolution of primeval galaxies, picked up in large and deep surveys due to their Lyman-alpha emission. I will show how Lyman-alpha emitters (LAEs) are an incredibly rare population of galaxies in the local Universe, but become dominant into the epoch of re-ionisation and that they have the properties and the number density necessary to dominate and drive cosmic re-ionisation. Lyman-α (Lyα) is intrinsically the brightest line emitted from active galaxies, but its resonant nature and susceptibility to dust as a rest-frame UV photon makes Lyα very hard to interpret due to the uncertain Lyα escape fraction, until now. By conducting large blind surveys at different cosmic times and the necessary spectroscopic follow-up, we have obtained a simple empirical relation that robustly retrieves the Lyα escape fraction as a function of Lyα rest-frame EW. We show that the relation constrains a well-defined anti-correlation between ionisation efficiency and dust extinction in Lyman-alpha emitters (LAEs) which is likely an evolutionary sequence for very young metal poor sources going through a LAE phase. We also reveal how those LAEs/primeval galaxies have high escape fractions of not just Lyman-alpha photons, but also LyC, and how the production and escape seem to be linked together. We are trying something new this year with leaving the Zoom call open after the formal hour of the seminar is up to allow the speaker, if they wish, to chat informally with anyone who is interested. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - David Sobral Time: Mar 18, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/64177331893?pwd=bzRRT3BjTFZtVDdnL08rdlg1VEpUQT09 Meeting ID: 641 7733 1893 Passcode: eSPORdIpAR -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Mar 18 09:58:33 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 18 Mar 2022 09:58:33 +0100 Subject: [Astronomy seminar] Astronomy Department Seminar - March 14th David Sobral In-Reply-To: <54f25263-56d0-1507-4963-6951d70f0491@astro.su.se> References: <54f25263-56d0-1507-4963-6951d70f0491@astro.su.se> Message-ID: Reminder of David's seminar in half an hour C On 14/03/2022 13:31, Chris Usher wrote: > > On Friday, March 18th at 10:30 we have our next seminar with David > Sobral (Lancaster) speaking via Zoom > > *Resolving the formation and evolution of primeval galaxies: from > re-ionisation to cosmic noon* > > I will present new results that reveal the nature and evolution of > primeval galaxies, picked up in large and deep surveys due to their > Lyman-alpha emission. I will show how Lyman-alpha emitters (LAEs) are > an incredibly rare population of galaxies in the local Universe, but > become dominant into the epoch of re-ionisation and that they have the > properties and the number density necessary to dominate and drive > cosmic re-ionisation. > > Lyman-α (Lyα) is intrinsically the brightest line emitted from active > galaxies, but its resonant nature and susceptibility to dust as a > rest-frame UV photon makes Lyα very hard to interpret due to the > uncertain Lyα escape fraction, until now. By conducting large blind > surveys at different cosmic times and the necessary spectroscopic > follow-up, we have obtained a simple empirical relation that robustly > retrieves the Lyα escape fraction as a function of Lyα rest-frame EW. > We show that the relation constrains a well-defined anti-correlation > between ionisation efficiency and dust extinction in Lyman-alpha > emitters (LAEs) which is likely an evolutionary sequence for very > young metal poor sources going through a LAE phase. We also reveal > how those LAEs/primeval galaxies have high escape fractions of not > just Lyman-alpha photons, but also LyC, and how the production and > escape seem to be linked together. > > We are trying something new this year with leaving the Zoom call open > after the formal hour of the seminar is up to allow the speaker, if > they wish, to chat informally with anyone who is interested. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar - David Sobral > Time: Mar 18, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/64177331893?pwd=bzRRT3BjTFZtVDdnL08rdlg1VEpUQT09 > > > Meeting ID: 641 7733 1893 > Passcode: eSPORdIpAR -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Mar 21 10:55:09 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 21 Mar 2022 10:55:09 +0100 Subject: [Astronomy seminar] =?utf-8?q?Astronomy_Department_Seminar_-_Marc?= =?utf-8?q?h_25th_Ad=C3=A9la=C3=AFde_Claeyssens?= Message-ID: On Friday, March 25th at 10:30 Adélaïde Claeyssens (Stockholm University) will be giving our next seminar. *The properties of lensed high redshift Lyman-alpha emitters* The circumgalactic medium (CGM) is closely linked to galaxy formation and evolution, but difficult to observe in emission at high redshift. I will present some first results from the Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS), a large sample of >600 lensed Lyman-alpha emitters (LAEs) observed with MUSE and HST towards massive galaxy clusters. Thanks to the strong lensing magnification and associated gain in spatial resolution, we can detect and characterize very faint galaxies, and the resolved properties of line emission from the circumgalactic medium (CGM). With such a statistical sample we can characterize Lyman-alpha haloes as small as 0.5 kpc (correcting for the lensing effect) and measure their intrinsic morphological properties such as extent, ellipticity, as well as the UV morphology and spatial offsets between the UV continuum and the Lyman-alpha emission. LLAMAS provides unique measurements on such properties at this redshift, beyond the reach of non-lensed deep fields, and are therefore crucial for understanding the CGM properties at z>3. We are trying something new this year with leaving the Zoom call open after the formal hour of the seminar is up to allow the speaker, if they wish, to chat informally with anyone who is interested. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Adélaïde Claeyssens Time: Mar 25, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66528043554?pwd=aWNlUGlOZCtCc01CdEpkR3FtMFlLdz09 Meeting ID: 665 2804 3554 Passcode: ICiLmiNGUi -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Mar 25 10:00:42 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 25 Mar 2022 10:00:42 +0100 Subject: [Astronomy seminar] =?utf-8?q?Astronomy_Department_Seminar_-_Mar?= =?utf-8?q?ch_25th_Ad=C3=A9la=C3=AFde_Claeyssens?= In-Reply-To: <376f47c3-9e38-8134-6957-a1951dc1678b@astro.su.se> References: <376f47c3-9e38-8134-6957-a1951dc1678b@astro.su.se> Message-ID: Reminder, Adélaïde's talk is in half an hour C On 21/03/2022 10:55, Chris Usher wrote: > > On Friday, March 25th at 10:30 Adélaïde Claeyssens (Stockholm > University) will be giving our next seminar. > > *The properties of lensed high redshift Lyman-alpha emitters* > > The circumgalactic medium (CGM) is closely linked to galaxy formation > and evolution, but difficult to observe in emission at high redshift. > I will present some first results from the Lensed Lyman-Alpha MUSE > Arcs Sample (LLAMAS), a large sample of >600 lensed Lyman-alpha > emitters (LAEs) observed with MUSE and HST towards massive galaxy > clusters. Thanks to the strong lensing magnification and associated > gain in spatial resolution, we can detect and characterize very faint > galaxies, and the resolved properties of line emission from the > circumgalactic medium (CGM). With such a statistical sample we can > characterize Lyman-alpha haloes as small as 0.5 kpc (correcting for > the lensing effect) and measure their intrinsic morphological > properties such as extent, ellipticity, as well as the UV morphology > and spatial offsets between the UV continuum and the Lyman-alpha > emission. LLAMAS provides unique measurements on such properties at > this redshift, beyond the reach of non-lensed deep fields, and are > therefore crucial for understanding the CGM properties at z>3. > > We are trying something new this year with leaving the Zoom call open > after the formal hour of the seminar is up to allow the speaker, if > they wish, to chat informally with anyone who is interested. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar - Adélaïde Claeyssens > Time: Mar 25, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/66528043554?pwd=aWNlUGlOZCtCc01CdEpkR3FtMFlLdz09 > > > Meeting ID: 665 2804 3554 > Passcode: ICiLmiNGUi -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Sun Mar 27 22:50:34 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Sun, 27 Mar 2022 22:50:34 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - April 1st Haakon Andresen Message-ID: Hello On Friday the 1st of April at 10:30, Haakon Andresen (Stockholm) will be giving our next seminar. This will be our first hybrid seminar - you are welcome to either attend in person in FC61 or via Zoom. After the seminar we will going for lunch with Haakon at Proviant. *Core-collapse Supernovae and Gravitational Waves: Where we stand and questions for the future* While significant progress has been made due to the advent of multi-dimensional numerical simulations, the exact nature of the core-collapse supernova has yet to be fully illuminated. Detecting gravitational waves from a core-collapse supernova would give us insight into the explosion mechanism. I will discuss the current status of core-collapse gravitational-wave astronomy, the progress made over the last decade, and open questions. Based on the aforementioned topics, I will motivate and describe the research I am currently performing at the department. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Haakon Andresen Time: Apr 1, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/68153379147?pwd=T0lrYzVUN1I4MGhGRFBQQ1RDYUdIUT09 Meeting ID: 681 5337 9147 Passcode: Fp52e96EXM -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Apr 1 10:13:25 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 1 Apr 2022 10:13:25 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - April 1st Haakon Andresen In-Reply-To: <2a0df516-cfd4-414a-ae99-1e4c64b49c22@astro.su.se> References: <2a0df516-cfd4-414a-ae99-1e4c64b49c22@astro.su.se> Message-ID: Reminder, Haakon's seminar is in 17 min both on Zoom and in FC61 C On 27/03/2022 22:50, Chris Usher wrote: > > Hello > > On Friday the 1st of April at 10:30, Haakon Andresen (Stockholm) will > be giving our next seminar. This will be our first hybrid seminar - > you are welcome to either attend in person in FC61 or via Zoom. After > the seminar we will going for lunch with Haakon at Proviant. > > *Core-collapse Supernovae and Gravitational Waves: Where we stand and > questions for the future* > > While significant progress has been made due to the advent of > multi-dimensional numerical simulations, the exact nature of the > core-collapse supernova has yet to be fully illuminated. Detecting > gravitational waves from a core-collapse supernova would give us > insight into the explosion mechanism. I will discuss the current > status of core-collapse gravitational-wave astronomy, the progress > made over the last decade, and open questions. Based on the > aforementioned topics, I will motivate and describe the research I am > currently performing at the department. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar - Haakon Andresen > Time: Apr 1, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/68153379147?pwd=T0lrYzVUN1I4MGhGRFBQQ1RDYUdIUT09 > > Meeting ID: 681 5337 9147 > Passcode: Fp52e96EXM > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Apr 4 11:48:57 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 4 Apr 2022 11:48:57 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - April 8th Fernando Buitrago Message-ID: Hello On Friday the 8th of April at 10:30, Fernando Buitrago (Valladolid/IA Portugal) will be giving our next seminar. This will be a hybrid seminar - you are welcome to either attend in person in FC61 or via Zoom. After the seminar we will going for lunch with Fernando at Proviant. Fernando will be visiting the department on Thursday and Friday. *The faintest surface brightness limits of high redshift galaxies* The Low Surface Brightness (LSB) regime is the last niche for studies of galaxy formation and evolution. It is of outstanding importance for investigating not only the smallest galaxies, but also for the most massive ones. We will review the state-of-the-art of how massive galaxies progressively change their properties over cosmic time, and how LSB describes this mass assembly. Going to the deepest Hubble Space Telescope fields, we will show our latest results looking for galaxy truncations, real galaxy edges whose existence is linked with the gas density threshold for star formation. Therefore, we obtain a new physically-motivated mass-size relation, whereby massive galaxies grow by a factor of two since z = 1 while at the same time increasing by an order of magnitude their stellar density at the truncation position. The retrieval of these galaxy limits will be very beneficial for the study of stellar haloes and also for elucidating dark matter halo sizes. We will also present our future plans for improving all these results by making use of JWST and Euclid forthcoming data. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Fernando Buitrago Time: Apr 8, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/69749792158 Meeting ID: 697 4979 2158 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Apr 8 10:00:33 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 8 Apr 2022 10:00:33 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - April 8th Fernando Buitrago In-Reply-To: References: Message-ID: Reminder - Fernando's seminar is in half an hour in FC61 or on Zoom On 04/04/2022 11:48, Chris Usher wrote: > > Hello > > On Friday the 8th of April at 10:30, Fernando Buitrago (Valladolid/IA > Portugal) will be giving our next seminar. This will be a hybrid > seminar - you are welcome to either attend in person in FC61 or via > Zoom. After the seminar we will going for lunch with Fernando at > Proviant. Fernando will be visiting the department on Thursday and Friday. > > *The faintest surface brightness limits of high redshift galaxies* > > The Low Surface Brightness (LSB) regime is the last niche for studies > of galaxy formation and evolution. It is of outstanding importance for > investigating not only the smallest galaxies, but also for the most > massive ones. We will review the state-of-the-art of how massive > galaxies progressively change their properties over cosmic time, and > how LSB describes this mass assembly. Going to the deepest Hubble > Space Telescope fields, we will show our latest results looking for > galaxy truncations, real galaxy edges whose existence is linked with > the gas density threshold for star formation. Therefore, we obtain a > new physically-motivated mass-size relation, whereby massive galaxies > grow by a factor of two since z = 1 while at the same time increasing > by an order of magnitude their stellar density at the truncation > position. The retrieval of these galaxy limits will be very beneficial > for the study of stellar haloes and also for elucidating dark matter > halo sizes. We will also present our future plans for improving all > these results by making use of JWST and Euclid forthcoming data. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar - Fernando Buitrago > Time: Apr 8, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/69749792158 > > Meeting ID: 697 4979 2158 > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Wed Apr 13 13:10:23 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Wed, 13 Apr 2022 11:10:23 +0000 Subject: [Astronomy seminar] Scholars at Risk seminar 19/04 Message-ID: On Tuesday 19/4 at 13:30 we will have a seminar by Johanna Wiklund (SU) about Scholars at Risk. You are welcome to join in FC61 (Astronomy Department). Scholars at Risk is an international human rights organization based in New York. Their purpose is to highlight the importance of academic freedom and to offer sanctuaries to scholars who live under threat in their home countries. Scholars at Risk collaborates with 500 universities worldwide and Stockholm University has been a member since 2016. SU departments with an interest in hosting a threatened scholar within their discipline will be sponsored by external funding and with support from the President’s office. To find out more about the possibilities for your department to engage in Scholars at Risk you are welcome to attend our information session on 19 April at 1.30 – 2.30. pm. You can also join via zoom: Topic: SAR Network Time: Apr 19, 2022 01:30 PM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/61727001638 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Tue Apr 19 09:17:09 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Tue, 19 Apr 2022 09:17:09 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - April 22nd Mike Barlow Message-ID: Hello On Friday the 22nd of April at 10:30, Mike Barlow (UCL) will be giving our next seminar. This will be a hybrid seminar - you are welcome to either attend in person in FC61 or via Zoom. Mike will be visiting the department that Friday and we will be going for lunch with him after the seminar. *Dust Formation by Supernovae* The large quantities of dust found in a number of high redshift galaxies has led to suggestions that core-collapse supernovae (CCSNe) are the main sources of their dust and has motivated the measurement of the dust masses formed by local and extragalactic CCSNe. A widely used technique for CCSN dust mass determination, namely the fitting of their optical-IR spectral energy distributions, is restricted to warmer dust emitting shortwards of 30 microns by the lack of sufficiently sensitive facilities operating at longer wavelengths. However, an alternative technique for measuring total dust masses is available, one which is insensitive to dust temperature. This method relies on the spectral modelling of the red-blue asymmetries in late-epoch optical emission line profiles, produced by dust within the ejecta that selectively absorbs red-shifted photons emitted from the far side of the ejecta. After reviewing earlier work on CCSN dust masses, I will report on dust masses obtained from line profile fitting for a large VLT and Gemini spectral survey of extragalactic CCSNe, some observed at epochs up to 60 years after outburst. Evidence will be presented for a slow growth in CCSN ejecta dust masses with time, taking approximately 30 years to saturate at a mean dust mass of 0.4 solar masses per CCSN. Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar Time: Apr 22, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/69462418973 Meeting ID: 694 6241 8973 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Tue Apr 19 11:11:30 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Tue, 19 Apr 2022 09:11:30 +0000 Subject: [Astronomy seminar] Reminder: Today Scholars at risk seminar Message-ID: Today at 13:30 we will have a seminar by Johanna Wiklund (SU) about Scholars at Risk. You are welcome to join in FC61 (Astronomy Department). Scholars at Risk is an international human rights organization based in New York. Their purpose is to highlight the importance of academic freedom and to offer sanctuaries to scholars who live under threat in their home countries. Scholars at Risk collaborates with 500 universities worldwide and Stockholm University has been a member since 2016. SU departments with an interest in hosting a threatened scholar within their discipline will be sponsored by external funding and with support from the President’s office. To find out more about the possibilities for your department to engage in Scholars at Risk you are welcome to attend our information session on 19 April at 1.30 – 2.30. pm. You can also join via zoom: Topic: SAR Network Time: Apr 19, 2022 01:30 PM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/61727001638 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Apr 22 09:59:49 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 22 Apr 2022 09:59:49 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - April 22nd Mike Barlow In-Reply-To: <1d1f4013-489a-b006-6af1-e110e4f7b0d6@astro.su.se> References: <1d1f4013-489a-b006-6af1-e110e4f7b0d6@astro.su.se> Message-ID: Reminder, Mike's talk is in half an hour in FC61 and on Zoom! C On 19/04/2022 09:17, Chris Usher wrote: > > Hello > > On Friday the 22nd of April at 10:30, Mike Barlow (UCL) will be giving > our next seminar. This will be a hybrid seminar - you are welcome to > either attend in person in FC61 or via Zoom. Mike will be visiting the > department that Friday and we will be going for lunch with him after > the seminar. > > *Dust Formation by Supernovae* > > The large quantities of dust found in a number of high redshift > galaxies has led to suggestions that core-collapse supernovae (CCSNe) > are the main sources of their dust and has motivated the measurement > of the dust masses formed by local and extragalactic CCSNe. A widely > used technique for CCSN dust mass determination, namely the fitting of > their optical-IR spectral energy distributions, is restricted to > warmer dust emitting shortwards of 30 microns by the lack of > sufficiently sensitive facilities operating at longer wavelengths. > However, an alternative technique for measuring total dust masses is > available, one which is insensitive to dust temperature. This method > relies on the spectral modelling of the red-blue asymmetries in > late-epoch optical emission line profiles, produced by dust within the > ejecta that selectively absorbs red-shifted photons emitted from the > far side of the ejecta. After reviewing earlier work on CCSN dust > masses, I will report on dust masses obtained from line profile > fitting for a large VLT and Gemini spectral survey of extragalactic > CCSNe, some observed at epochs up to 60 years after outburst. Evidence > will be presented for a slow growth in CCSN ejecta dust masses with > time, taking approximately 30 years to saturate at a mean dust mass of > 0.4 solar masses per CCSN. > > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar > Time: Apr 22, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/69462418973 > > Meeting ID: 694 6241 8973 > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Apr 25 11:09:13 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 25 Apr 2022 11:09:13 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - April 29th Renske Smit Message-ID: On Friday, April 29th Renske Smit (LJMU) will be giving our next seminar via Zoom. *An ALMA view of galaxies in the Epoch of Reionization* In the past decade hundreds of galaxy candidates have been identified in the Epoch of Reionization (EoR), selected from their rest-frame UV light. Only a handful of these sources, however, have spectroscopic redshift determinations and we have limited understanding of their properties. ALMA is currently transforming this field by identifying massive ISM reservoirs at z>6.5 from bright [CII] line emission. I will describe how we obtained the first spectroscopic confirmations of galaxies in the EoR with ALMA, where Lya often remains undetected due to the intervening neutral IGM, and how ALMA is now rapidly becoming a 'redshift machine' for the distant Universe. With the spectroscopic redshifts in hand, we are in a position to start probing the physical properties of these sources, including their fine structure line ratios, dust content and temperature, structural properties and low-resolution kinematics. A picture is starting to form of complex structures within these galaxies with distinct dusty and UV-bright components which exhibit different ISM properties. Moreover, we find evidence that some of these galaxies are already rotation-dominated disk-like sources, just 800 million years after the Big Bang. We are trying something new this year with leaving the Zoom call open after the formal hour of the seminar is up to allow the speaker, if they wish, to chat informally with anyone who is interested. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Renske Smit Time: Apr 29, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/69717398551 Meeting ID: 697 1739 8551 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Wed Apr 27 11:01:26 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Wed, 27 Apr 2022 11:01:26 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - April 29th Renske Smit In-Reply-To: References: Message-ID: Unfortunately our speaker has had to cancel so there will be no seminar this week. Chris On 25/04/2022 11:09, Chris Usher wrote: > > On Friday, April 29th Renske Smit (LJMU) will be giving our next > seminar via Zoom. > > *An ALMA view of galaxies in the Epoch of Reionization* > > In the past decade hundreds of galaxy candidates have been identified > in the Epoch of Reionization (EoR), selected from their rest-frame UV > light. Only a handful of these sources, however, have spectroscopic > redshift determinations and we have limited understanding of their > properties. ALMA is currently transforming this field by identifying > massive ISM reservoirs at z>6.5 from bright [CII] line emission. I > will describe how we obtained the first spectroscopic confirmations of > galaxies in the EoR with ALMA, where Lya often remains undetected due > to the intervening neutral IGM, and how ALMA is now rapidly becoming a > 'redshift machine' for the distant Universe. With the spectroscopic > redshifts in hand, we are in a position to start probing the physical > properties of these sources, including their fine structure line > ratios, dust content and temperature, structural properties and > low-resolution kinematics. A picture is starting to form of complex > structures within these galaxies with distinct dusty and UV-bright > components which exhibit different ISM properties. Moreover, we find > evidence that some of these galaxies are already rotation-dominated > disk-like sources, just 800 million years after the > Big Bang. > > We are trying something new this year with leaving the Zoom call open > after the formal hour of the seminar is up to allow the speaker, if > they wish, to chat informally with anyone who is interested. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar - Renske Smit > Time: Apr 29, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/69717398551 > > Meeting ID: 697 1739 8551 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon May 2 09:42:38 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 2 May 2022 07:42:38 +0000 Subject: [Astronomy seminar] Astronomy seminar Message-ID: On Friday the 06th of May at 10:30, Alex Pietrow (SU) will be giving our next seminar. This will be a hybrid seminar - you are welcome to either attend in person in FC61 or via Zoom. Physical properties of chromospheric features, plage, peacock jets, and calibrating it all The chromosphere is a complex and dynamic layer of the solar atmosphere, largely dominated by the local magnetic field configuration. It acts as an important interface between the photosphere below it and the hot corona above. However, studying this layer is not straightforward, as it is largely transparent in optical wavelengths. On top of that most of its observable radiation is formed in conditions far from thermodynamic equilibrium, and thus only partially sensitive to local plasma conditions. Observations of the active features found in the chromosphere such as plage, fibrils, and jets, are therefore more difficult to interpret than emission from active features in the photosphere. In this seminar I will discuss two types of chromospheric features, namely plage and a peacock jet. Zoom Meeting: Topic: Physical properties of chromospheric features, plage, peacock jets, and calibrating it all Time: May 6, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/68066058145 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri May 6 09:32:57 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 6 May 2022 07:32:57 +0000 Subject: [Astronomy seminar] Reminder: Astronomy Seminar Message-ID: On Friday the 06th of May at 10:30, Alex Pietrow (SU) will be giving our next seminar. This will be a hybrid seminar - you are welcome to either attend in person in FC61 or via Zoom. Physical properties of chromospheric features, plage, peacock jets, and calibrating it all The chromosphere is a complex and dynamic layer of the solar atmosphere, largely dominated by the local magnetic field configuration. It acts as an important interface between the photosphere below it and the hot corona above. However, studying this layer is not straightforward, as it is largely transparent in optical wavelengths. On top of that most of its observable radiation is formed in conditions far from thermodynamic equilibrium, and thus only partially sensitive to local plasma conditions. Observations of the active features found in the chromosphere such as plage, fibrils, and jets, are therefore more difficult to interpret than emission from active features in the photosphere. In this seminar I will discuss two types of chromospheric features, namely plage and a peacock jet. Zoom Meeting: Topic: Physical properties of chromospheric features, plage, peacock jets, and calibrating it all Time: May 6, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/68066058145 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon May 9 15:45:32 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 9 May 2022 13:45:32 +0000 Subject: [Astronomy seminar] Astronomy seminar 13/05 Message-ID: On Friday 13th of May at 10:30 we will have our next Astronomy seminar. The speaker is Andrew Cameron (St.Andrews). The seminar will be on zoom only. Please join in time. Title: Observing the Sun with stellar radial-velocity instruments: new approaches for weighing Earth analogues. Abstract: With the launch of the PLATO mission only a few years away, the exoplanet detection community is working hard on new approaches to extreme-precision radial-velocity (EPRV) measurements. Candidate Earth analogues detected by PLATO will have orbital periods of order hundreds of days, and reflex orbital-motion signals with amplitudes of order 10 cm s$^{-1}$. In this talk I will discuss some of the instrumental and data-analysis capabilities needed to detect the reflex orbital motion of such planets’ host stars, in order to meaure the planets’ masses. High instrumental throughput and long-term thermal stability, precise wavelength calibration and drift monitoring, and efficient mitigation of telluric absorption are mandatory. New instruments are already approaching the necessary precision. The stars themselves present the most formidable remaining challenge, as p-mode oscillations, granular convection and magnetic effects on surface brightness and velocity fields alter the shapes and relative strengths of spectral lines on time scales from minutes to years. To connect these to known surface features on the Sun, I will present data from stellar EPRV instruments which now observe the Sun all day, every day via fibre feeds from small, disc-integrating telescopes. The Sun's own reflex motion about the solar-system barycentre reminds us that the radial-velocity signal of a true Earth analogue will have to be disentangled from the reflex motions of other non-transiting planets in the same system. Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Observing the Sun with stellar radial-velocity instruments: new approaches for weighing Earth analogues. Time: May 13, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/68066058145 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri May 13 08:52:20 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 13 May 2022 06:52:20 +0000 Subject: [Astronomy seminar] Reminder: Astronomy seminar 13/05 In-Reply-To: References: Message-ID: Today at 10:30 we will have our next Astronomy seminar. The speaker is Andrew Cameron (St.Andrews). The seminar will be on zoom only. Please join in time. Title: Observing the Sun with stellar radial-velocity instruments: new approaches for weighing Earth analogues. Abstract: With the launch of the PLATO mission only a few years away, the exoplanet detection community is working hard on new approaches to extreme-precision radial-velocity (EPRV) measurements. Candidate Earth analogues detected by PLATO will have orbital periods of order hundreds of days, and reflex orbital-motion signals with amplitudes of order 10 cm s$^{-1}$. In this talk I will discuss some of the instrumental and data-analysis capabilities needed to detect the reflex orbital motion of such planets’ host stars, in order to meaure the planets’ masses. High instrumental throughput and long-term thermal stability, precise wavelength calibration and drift monitoring, and efficient mitigation of telluric absorption are mandatory. New instruments are already approaching the necessary precision. The stars themselves present the most formidable remaining challenge, as p-mode oscillations, granular convection and magnetic effects on surface brightness and velocity fields alter the shapes and relative strengths of spectral lines on time scales from minutes to years. To connect these to known surface features on the Sun, I will present data from stellar EPRV instruments which now observe the Sun all day, every day via fibre feeds from small, disc-integrating telescopes. The Sun's own reflex motion about the solar-system barycentre reminds us that the radial-velocity signal of a true Earth analogue will have to be disentangled from the reflex motions of other non-transiting planets in the same system. Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Observing the Sun with stellar radial-velocity instruments: new approaches for weighing Earth analogues. Time: May 13, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/68066058145 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon May 16 10:19:30 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 16 May 2022 10:19:30 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - May 20th Ted Mackereth Message-ID: On Friday, May 20th at *14:00* Ted Mackereth (CITA/Dunlap) will give the seminar via Zoom. Please note the later time. *Unravelling the assembly history of the Milky Way: Observations, Simulations, Genetic Modification and... Sausages?* In order to properly understand much of the physics that governs our Universe and forms the grand structures that we see in it today, we must understand the mass assembly of galaxies. The Milky Way is perhaps the only galaxy for which we might one day fully reconstruct its assembly history, piece by piece, star by star. In this talk, I will show how, through a combination of industrial-scale observational surveys and detailed numerical simulations, we can begin to both constrain and understand the effects of the Milky Way’s history of assembly. I will show how such simulations can provide links between the present day properties of Milky Way stellar populations and it’s early dark matter assembly, and how these predictions can be directly tested using data from Gaia, the SDSS/APOGEE survey and Kepler, K2 and TESS. Finally, I will paint a picture of the future of the mission to use the Milky Way and nearby galaxies as a tool for understanding galaxy formation on a general basis. We are trying something new this year with leaving the Zoom call open after the formal hour of the seminar is up to allow the speaker, if they wish, to chat informally with anyone who is interested. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar - Ted Mackereth Time: May 20, 2022 02:00 PM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/61883141606 Meeting ID: 618 8314 1606 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri May 20 13:05:27 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 20 May 2022 13:05:27 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - May 20th Ted Mackereth In-Reply-To: <09e4b64c-3e81-9d55-23d6-6b63b0b65220@astro.su.se> References: <09e4b64c-3e81-9d55-23d6-6b63b0b65220@astro.su.se> Message-ID: Reminder of Ted's seminar on Zoom in 55 minutes C On 16/05/2022 10:19, Chris Usher wrote: > > On Friday, May 20th at *14:00* Ted Mackereth (CITA/Dunlap) will give > the seminar via Zoom. Please note the later time. > > *Unravelling the assembly history of the Milky Way: Observations, > Simulations, Genetic Modification and... Sausages?* > > In order to properly understand much of the physics that governs our > Universe and forms the grand structures that we see in it today, we > must understand the mass assembly of galaxies. The Milky Way is > perhaps the only galaxy for which we might one day fully reconstruct > its assembly history, piece by piece, star by star. In this talk, I > will show how, through a combination of industrial-scale observational > surveys and detailed numerical simulations, we can begin to both > constrain and understand the effects of the Milky Way’s history of > assembly. I will show how such simulations can provide links between > the present day properties of Milky Way stellar populations and it’s > early dark matter assembly, and how these predictions can be directly > tested using data from Gaia, the SDSS/APOGEE survey and Kepler, K2 and > TESS. Finally, I will paint a picture of the future of the mission to > use the Milky Way and nearby galaxies as a tool for understanding > galaxy formation on a general basis. > > We are trying something new this year with leaving the Zoom call open > after the formal hour of the seminar is up to allow the speaker, if > they wish, to chat informally with anyone who is interested. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar - Ted Mackereth > Time: May 20, 2022 02:00 PM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/61883141606 > > Meeting ID: 618 8314 1606 > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon May 23 16:03:02 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 23 May 2022 16:03:02 +0200 Subject: [Astronomy seminar] Thesis Seminar - May 25th Aurore Betranhandy Message-ID: On *Wednesday* May 25th at 10:30 in FC 61 and on Zoom Aurore Betranhandy (Stockholm) will be giving a seminar on her thesis work. Please note the unusual day due to the klämdag on Friday. *Neutrino interactions and axion emission impact on core-collapse supernova simulations* Core-Collapse Supernovae (CCSNe) are important phenomena in the scope of nucleosynthesis and, as the final stage of massive stars’ life, they are key processes in the understanding of stellar evolution. They also are the birthplace of neutron stars and black holes, therefore they play a major role in the modelling and understanding of compact object mergers. While CCSNe have been observed for a long time, it is mainly through electromagnetic radiation. This channel gives us precious information about the explosion energy and nucleosynthesis, but fails to inform us about the collapse and initial explosion mechanism. While other observational channels are becoming available, through neutrino detection and gravitational waves, we are still waiting for a galactic CCSN to get an appropriate signal giving us insight on the explosion mechanism. We, therefore, have to rely on simulations for now. CCSN simulations have been performed for 60 years, improving decade after decade, and are now able to produce systematic self-consistent explosions. Several parameters impact the final outcome of our simulations, originating from different physics treatments, such as the gravity, neutrino transport and interactions, micro-physics through the equation of state, or magnetic fields. To understand the explosion mechanism behind a CCSN, we need to study the impact of each of these uncertain pieces of physics. In this thesis, I focused on the impact of the emission of heavy-lepton neutrinos and axions on the explosion, concentrated on the early proto-neutron star cooling. I explain details of the CCSN process, as well as some of the particle physics I focused on. I show how a change in heavy-lepton neutrino and axion emissions can accelerate the early proto-neutron star cooling and subsequently help the explosion. The schedule of upcoming seminars can be found here: https://ttt.astro.su.se/ical/astro-seminars.ics Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Seminar - Aurore Betranhandy Time: May 25, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/66204962080 Meeting ID: 662 0496 2080 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Wed May 25 10:10:37 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Wed, 25 May 2022 10:10:37 +0200 Subject: [Astronomy seminar] Thesis Seminar - May 25th Aurore Betranhandy In-Reply-To: <71900a2b-a30d-c44f-54ff-f7d32e842786@astro.su.se> References: <71900a2b-a30d-c44f-54ff-f7d32e842786@astro.su.se> Message-ID: Reminder of Aurore's seminar in 20 min C On 23/05/2022 16:03, Chris Usher wrote: > > On *Wednesday* May 25th at 10:30 in FC 61 and on Zoom Aurore > Betranhandy (Stockholm) will be giving a seminar on her thesis work. > Please note the unusual day due to the klämdag on Friday. > > *Neutrino interactions and axion emission impact on core-collapse > supernova simulations* > > Core-Collapse Supernovae (CCSNe) are important phenomena in the scope > of nucleosynthesis and, as the final stage of massive stars’ life, > they are key processes in the understanding of stellar evolution. They > also are the birthplace of neutron stars and black holes, therefore > they play a major role in the modelling and understanding of compact > object mergers. While CCSNe have been observed for a long time, it is > mainly through electromagnetic radiation. This channel gives us > precious information about the explosion energy and nucleosynthesis, > but fails to inform us about the collapse and initial explosion > mechanism. While other observational channels are becoming available, > through neutrino detection and gravitational waves, we are still > waiting for a galactic CCSN to get an appropriate signal giving us > insight on the explosion mechanism. We, therefore, have to rely on > simulations for now. CCSN simulations have been performed for 60 > years, improving decade after decade, and are now able to produce > systematic self-consistent explosions. Several parameters impact the > final outcome of our simulations, originating from different physics > treatments, such as the gravity, neutrino transport and interactions, > micro-physics through the equation of state, or magnetic fields. To > understand the explosion mechanism behind a CCSN, we need to study the > impact of each of these uncertain pieces of physics. In this thesis, I > focused on the impact of the emission of heavy-lepton neutrinos and > axions on the explosion, concentrated on the early proto-neutron star > cooling. I explain details of the CCSN process, as well as some of the > particle physics I focused on. I show how a change in heavy-lepton > neutrino and axion emissions can accelerate the early proto-neutron > star cooling and subsequently help the explosion. > > The schedule of upcoming seminars can be found here: > https://ttt.astro.su.se/ical/astro-seminars.ics > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Seminar - Aurore Betranhandy > Time: May 25, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/66204962080 > > Meeting ID: 662 0496 2080 > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Wed May 25 10:18:02 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Wed, 25 May 2022 10:18:02 +0200 Subject: [Astronomy seminar] Thesis Seminar - May 25th Aurore Betranhandy In-Reply-To: <71900a2b-a30d-c44f-54ff-f7d32e842786@astro.su.se> References: <71900a2b-a30d-c44f-54ff-f7d32e842786@astro.su.se> Message-ID: Since there is a bunch of students who look like they are sitting an exam in FC61, Aurore will now be speaking from Aina Elvius (C6:1038) and on the same Zoom link. C On 23/05/2022 16:03, Chris Usher wrote: > > On *Wednesday* May 25th at 10:30 in FC 61 and on Zoom Aurore > Betranhandy (Stockholm) will be giving a seminar on her thesis work. > Please note the unusual day due to the klämdag on Friday. > > *Neutrino interactions and axion emission impact on core-collapse > supernova simulations* > > Core-Collapse Supernovae (CCSNe) are important phenomena in the scope > of nucleosynthesis and, as the final stage of massive stars’ life, > they are key processes in the understanding of stellar evolution. They > also are the birthplace of neutron stars and black holes, therefore > they play a major role in the modelling and understanding of compact > object mergers. While CCSNe have been observed for a long time, it is > mainly through electromagnetic radiation. This channel gives us > precious information about the explosion energy and nucleosynthesis, > but fails to inform us about the collapse and initial explosion > mechanism. While other observational channels are becoming available, > through neutrino detection and gravitational waves, we are still > waiting for a galactic CCSN to get an appropriate signal giving us > insight on the explosion mechanism. We, therefore, have to rely on > simulations for now. CCSN simulations have been performed for 60 > years, improving decade after decade, and are now able to produce > systematic self-consistent explosions. Several parameters impact the > final outcome of our simulations, originating from different physics > treatments, such as the gravity, neutrino transport and interactions, > micro-physics through the equation of state, or magnetic fields. To > understand the explosion mechanism behind a CCSN, we need to study the > impact of each of these uncertain pieces of physics. In this thesis, I > focused on the impact of the emission of heavy-lepton neutrinos and > axions on the explosion, concentrated on the early proto-neutron star > cooling. I explain details of the CCSN process, as well as some of the > particle physics I focused on. I show how a change in heavy-lepton > neutrino and axion emissions can accelerate the early proto-neutron > star cooling and subsequently help the explosion. > > The schedule of upcoming seminars can be found here: > https://ttt.astro.su.se/ical/astro-seminars.ics > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Seminar - Aurore Betranhandy > Time: May 25, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/66204962080 > > Meeting ID: 662 0496 2080 > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon May 30 13:58:27 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 30 May 2022 11:58:27 +0000 Subject: [Astronomy seminar] Astronomy Seminar 3/6 Message-ID: On Friday 3/6 at 10:30 we will have our next Astronomy seminar. The speaker is Jayant Joshi (Indian Institute of Astrophysics). The seminar will be on zoom only. Please join in time. Signatures of ubiquitous magnetic reconnection in the lower solar atmosphere Magnetic reconnection is a fundamental mechanism for many dynamic and transient events in the solar atmosphere, such as flares, coronal mass ejections (CMEs), jets, Ellerman bombs, ultra-violet (UV) bursts, and x-ray bright points. Ellerman Bomb is a magnetic reconnection phenomenon in the solar lower atmosphere, manifesting as intense brightenings in the wings of the hydrogen Balmer lines. Recently, it has been found that Ellerman-like brightenings also exist in the quiet sun and are known as quiet Sun Ellerman bombs. These are a signature of the fundamental process of magnetic reconnection at the smallest observable scale in the lower solar atmosphere. The speaker will present high spatio-temporal observations in the hydrogen Blamer-β line which reveal the ubiquitous presence of magnetic reconnection in the lower solar atmosphere. The ubiquitous small-scale reconnection events would be the key to understanding the dissipation of quiet-Sun magnetic energy and the reconfiguration of magnetic fields. Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Signatures of ubiquitous magnetic reconnection in the lower solar atmosphere Time: Jun 3, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/68066058145 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Jun 3 08:22:41 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 3 Jun 2022 06:22:41 +0000 Subject: [Astronomy seminar] Reminder: Astronomy seminar today Message-ID: Today at 10:30 we will have our next Astronomy seminar. The speaker is Jayant Joshi (Indian Institute of Astrophysics). The seminar will be on zoom only. Please join in time. Signatures of ubiquitous magnetic reconnection in the lower solar atmosphere Magnetic reconnection is a fundamental mechanism for many dynamic and transient events in the solar atmosphere, such as flares, coronal mass ejections (CMEs), jets, Ellerman bombs, ultra-violet (UV) bursts, and x-ray bright points. Ellerman Bomb is a magnetic reconnection phenomenon in the solar lower atmosphere, manifesting as intense brightenings in the wings of the hydrogen Balmer lines. Recently, it has been found that Ellerman-like brightenings also exist in the quiet sun and are known as quiet Sun Ellerman bombs. These are a signature of the fundamental process of magnetic reconnection at the smallest observable scale in the lower solar atmosphere. The speaker will present high spatio-temporal observations in the hydrogen Blamer-β line which reveal the ubiquitous presence of magnetic reconnection in the lower solar atmosphere. The ubiquitous small-scale reconnection events would be the key to understanding the dissipation of quiet-Sun magnetic energy and the reconfiguration of magnetic fields. Carolina Robustini is inviting you to a scheduled Zoom meeting. Topic: Signatures of ubiquitous magnetic reconnection in the lower solar atmosphere Time: Jun 3, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/68066058145 Carolina Robustini Inst. f. Solar Physics, Dept. of Astronomy, Stockholm University AlbaNova University Centre, SE-10691 Stockholm, Sweden Email: carolina.robustini at astro.su.se -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Jun 13 16:07:52 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 13 Jun 2022 16:07:52 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - June 17th Jennifer Barnes Message-ID: On Friday, June 17 at *16:00 *Jennifer Barns (KITP) will be giving the Astronomy Department Seminar on Zoom. Please note the later time. *Searching for alternative sources of r-process elements* Rapid neutron capture (r-process) nucleosynthesis produces roughly half of the elements in the Periodic Table more massive than iron. The unusual conditions required for a successful r-process, in particular the requisite high flux of (unstable) free neutrons, have made the astrophysical site(s) in which the r-process occurs an enduring mystery. Observations of the first detected neutron star merger, GW170817, in both electromagnetic and gravitational radiation yielded evidence that merging neutron stars, long favored theoretically as r-process sources, did indeed undergo heavy element nucleosynthesis. However, these same observations suggested that neutron star mergers may not be unique in their ability to produce r-process elements. I will present new insights on r-process sources, with a particular focus on rare supernova explosions, and discuss how radiation from explosive r-process transients may help us unlock the origin of the heaviest elements in the Universe. We are trying something new this year with leaving the Zoom call open after the formal hour of the seminar is up to allow the speaker, if they wish, to chat informally with anyone who is interested. Thanks Chris and Carolina Christopher Usher is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar Jennifer Barnes Time: Jun 17, 2022 04:00 PM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/67130319688 Meeting ID: 671 3031 9688 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Jun 17 10:30:31 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 17 Jun 2022 10:30:31 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - June 17th Jennifer Barnes In-Reply-To: <77ba7d48-c7f4-f958-16c5-2a39f952e501@astro.su.se> References: <77ba7d48-c7f4-f958-16c5-2a39f952e501@astro.su.se> Message-ID: Reminder that the last astronomy seminar of the academic year will be at 16:00 today. C On 13/06/2022 16:07, Chris Usher wrote: > > On Friday, June 17 at *16:00 *Jennifer Barns (KITP) will be giving the > Astronomy Department Seminar on Zoom. Please note the later time. > > *Searching for alternative sources of r-process elements* > > Rapid neutron capture (r-process) nucleosynthesis produces roughly > half of the elements in the Periodic Table more massive than iron. The > unusual conditions required for a successful r-process, in particular > the requisite high flux of (unstable) free neutrons, have made the > astrophysical site(s) in which the r-process occurs an enduring > mystery. Observations of the first detected neutron star merger, > GW170817, in both electromagnetic and gravitational radiation yielded > evidence that merging neutron stars, long favored theoretically as > r-process sources, did indeed undergo heavy element nucleosynthesis. > However, these same observations suggested that neutron star mergers > may not be unique in their ability to produce r-process elements. I > will present new insights on r-process sources, with a particular > focus on rare supernova explosions, and discuss how radiation from > explosive r-process transients may help us unlock the origin of the > heaviest elements in the Universe. > > We are trying something new this year with leaving the Zoom call open > after the formal hour of the seminar is up to allow the speaker, if > they wish, to chat informally with anyone who is interested. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar Jennifer Barnes > Time: Jun 17, 2022 04:00 PM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/67130319688 > > Meeting ID: 671 3031 9688 > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Jun 17 15:33:46 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 17 Jun 2022 15:33:46 +0200 Subject: [Astronomy seminar] Astronomy Department Seminar - June 17th Jennifer Barnes In-Reply-To: <77ba7d48-c7f4-f958-16c5-2a39f952e501@astro.su.se> References: <77ba7d48-c7f4-f958-16c5-2a39f952e501@astro.su.se> Message-ID: Reminder of Jennifer's seminar in 26 minutes C On 13/06/2022 16:07, Chris Usher wrote: > > On Friday, June 17 at *16:00 *Jennifer Barns (KITP) will be giving the > Astronomy Department Seminar on Zoom. Please note the later time. > > *Searching for alternative sources of r-process elements* > > Rapid neutron capture (r-process) nucleosynthesis produces roughly > half of the elements in the Periodic Table more massive than iron. The > unusual conditions required for a successful r-process, in particular > the requisite high flux of (unstable) free neutrons, have made the > astrophysical site(s) in which the r-process occurs an enduring > mystery. Observations of the first detected neutron star merger, > GW170817, in both electromagnetic and gravitational radiation yielded > evidence that merging neutron stars, long favored theoretically as > r-process sources, did indeed undergo heavy element nucleosynthesis. > However, these same observations suggested that neutron star mergers > may not be unique in their ability to produce r-process elements. I > will present new insights on r-process sources, with a particular > focus on rare supernova explosions, and discuss how radiation from > explosive r-process transients may help us unlock the origin of the > heaviest elements in the Universe. > > We are trying something new this year with leaving the Zoom call open > after the formal hour of the seminar is up to allow the speaker, if > they wish, to chat informally with anyone who is interested. > > Thanks > Chris and Carolina > > Christopher Usher is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar Jennifer Barnes > Time: Jun 17, 2022 04:00 PM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/67130319688 > > Meeting ID: 671 3031 9688 > -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Aug 22 16:46:31 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 22 Aug 2022 16:46:31 +0200 Subject: [Astronomy seminar] Thesis Seminar - August 26th Axel Runnholm Message-ID: On Friday August 26th at 10:30 in FC 61 and on Zoom, Axel Runnholm (Stockholm) will be giving a seminar on his thesis work. Using Lyα to illuminate the circumgalactic medium and the Epoch of Reionization—Lessons from low redshift During recent years the Lyα emission line has come to the fore as a potentially very powerful astrophysical tool and is now routinely used to find galaxies at the very highest redshifts. However, using Lyα is complicated by the fact that it is a resonant line, which means that it undergoes radiative transfer in neutral hydrogen. This makes Lyα observations very difficult to interpret, but it also means that Lyα can provide information about the neutral hydrogen in the universe, giving it the potential to, for instance, map the progression of the Epoch of Reionization. Even though Lyα is relatively easy to detect at high redshift we cannot study the details of the escape process there, due to the lack of additional information about the emitting galaxies. In order to understand Lyα in detail, we need to observe galaxies at much lower redshift where we can get more information. This is the main driver of the projects included in my thesis which I will present and which focuses on furthering our understanding of Lyα using local universe observations. Studying both spectral and spatial distributions of Lyα, and comparing high and low redshift observations, we find that Lyα properties of galaxies seem remarkably unchanged as a function of cosmic time strongly supporting the notion that we can use low-z as a way to understand processes occurring at high-z. We use our low-z observations to give some of the first indications of the source of spatially extended Lyα emission which is ubiquitous at high-z, showing that it may in fact partially be produced by in-situ recombination. Additionally I will present results demonstrating that that Lyα escape is a strongly multivariate issue and that using simple machine learning techniques can both help us predict Lyα and determine what the main drivers of Lyα emission are, and discuss how we can use this to learn more about, for instance, the Epoch of Reionization. Thanks! Eliot and Kris Eliot Ayache is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar Axel Runnholm Time: Aug 26, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/63770823546 Meeting ID: 637 7082 3546 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Tue Aug 23 09:29:58 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Tue, 23 Aug 2022 09:29:58 +0200 Subject: [Astronomy seminar] [URGENT!] Thesis Seminar - August 26th Axel Runnholm In-Reply-To: References: Message-ID: Hi Axel, Have you received this email? No one else in the department has. If you have, I need the email header (cf forwarded info underneath), which you can access apparently. I’ll look for a solution on my side too. So people do show up at your seminar. Thanks! Eliot On 2022-08-22T18:55:07+02:00, eliot.ayache at astro.su.se wrote: > Hi Sergio, > > Thanks for the quick response! > The sender address was eliot.ayache at astro.su.se . I attached the full > message below. IT Services have asked for the full message header. I'm not sure you (as the sender) would have it, but maybe Axel has received his copy and can provide the information. (Note: some mail clients make it difficult to see the full headers. Some mail servers too, in fact: Exchange stores headers in a database, and what comes out isn't always what went in. You may have to study the documentation for your mail client, or use a friendlier client such as Mutt. See what you can do.) > On 22 Aug 2022, at 16:46, Eliot Ayache wrote: > > On Friday August 26th at 10:30 in FC 61 and on Zoom, Axel Runnholm (Stockholm) will be giving a seminar on his thesis work. > > > Using Lyα to illuminate the circumgalactic medium and the Epoch of Reionization—Lessons from low redshift > > During recent years the Lyα emission line has come to the fore as a potentially very powerful astrophysical tool and is now routinely used to find galaxies at the very highest redshifts. However, using Lyα is complicated by the fact that it is a resonant line, which means that it undergoes radiative transfer in neutral hydrogen. This makes Lyα observations very difficult to interpret, but it also means that Lyα can provide information about the neutral hydrogen in the universe, giving it the potential to, for instance, map the progression of the Epoch of Reionization. > Even though Lyα is relatively easy to detect at high redshift we cannot study the details of the escape process there, due to the lack of additional information about the emitting galaxies. In order to understand Lyα in detail, we need to observe galaxies at much lower redshift where we can get more information. This is the main driver of the projects included in my thesis which I will present and which focuses on furthering our understanding of Lyα using local universe observations. > Studying both spectral and spatial distributions of Lyα, and comparing high and low redshift observations, we find that Lyα properties of galaxies seem remarkably unchanged as a function of cosmic time strongly supporting the notion that we can use low-z as a way to understand processes occurring at high-z. We use our low-z observations to give some of the first indications of the source of spatially extended Lyα emission which is ubiquitous at high-z, showing that it may in fact partially be produced by in-situ recombination. > Additionally I will present results demonstrating that that Lyα escape is a strongly multivariate issue and that using simple machine learning techniques can both help us predict Lyα and determine what the main drivers of Lyα emission are, and discuss how we can use this to learn more about, for instance, the Epoch of Reionization. > > > Thanks! > Eliot and Kris > > Eliot Ayache is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar Axel Runnholm > Time: Aug 26, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/63770823546 > > Meeting ID: 637 7082 3546 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Aug 26 10:13:06 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 26 Aug 2022 10:13:06 +0200 Subject: [Astronomy seminar] Thesis Seminar - August 26th Axel Runnholm In-Reply-To: References: Message-ID: Reminder about Axel Runnholm’s seminar in 18 minutes in FC61 (and on zoom). See you there! Eliot > On 22 Aug 2022, at 16:46, Eliot Ayache wrote: > > On Friday August 26th at 10:30 in FC 61 and on Zoom, Axel Runnholm (Stockholm) will be giving a seminar on his thesis work. > > > Using Lyα to illuminate the circumgalactic medium and the Epoch of Reionization—Lessons from low redshift > > During recent years the Lyα emission line has come to the fore as a potentially very powerful astrophysical tool and is now routinely used to find galaxies at the very highest redshifts. However, using Lyα is complicated by the fact that it is a resonant line, which means that it undergoes radiative transfer in neutral hydrogen. This makes Lyα observations very difficult to interpret, but it also means that Lyα can provide information about the neutral hydrogen in the universe, giving it the potential to, for instance, map the progression of the Epoch of Reionization. > Even though Lyα is relatively easy to detect at high redshift we cannot study the details of the escape process there, due to the lack of additional information about the emitting galaxies. In order to understand Lyα in detail, we need to observe galaxies at much lower redshift where we can get more information. This is the main driver of the projects included in my thesis which I will present and which focuses on furthering our understanding of Lyα using local universe observations. > Studying both spectral and spatial distributions of Lyα, and comparing high and low redshift observations, we find that Lyα properties of galaxies seem remarkably unchanged as a function of cosmic time strongly supporting the notion that we can use low-z as a way to understand processes occurring at high-z. We use our low-z observations to give some of the first indications of the source of spatially extended Lyα emission which is ubiquitous at high-z, showing that it may in fact partially be produced by in-situ recombination. > Additionally I will present results demonstrating that that Lyα escape is a strongly multivariate issue and that using simple machine learning techniques can both help us predict Lyα and determine what the main drivers of Lyα emission are, and discuss how we can use this to learn more about, for instance, the Epoch of Reionization. > > > Thanks! > Eliot and Kris > > Eliot Ayache is inviting you to a scheduled Zoom meeting. > > Topic: Astronomy Department Seminar Axel Runnholm > Time: Aug 26, 2022 10:30 AM Stockholm > > Join Zoom Meeting > https://stockholmuniversity.zoom.us/j/63770823546 > > Meeting ID: 637 7082 3546 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Aug 29 09:01:27 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 29 Aug 2022 09:01:27 +0200 Subject: [Astronomy seminar] Thesis Seminar - September 2nd Roberta Morosin Message-ID: On Friday September 2nd at 10:30 in FC 61 (Albanova) and on Zoom, Roberta Morosin (Stockholm) will be giving a seminar on her thesis work. Solar magnetic fields in chromospheric structures - Approach to the chromospheric heating problem Our knowledge of the heating mechanisms that are at work in the chromosphere remains highly unconstrained from observational studies. While many heating candidates have been proposed in theoretical studies, the exact contribution from each of them is still unknown. The problem is rather difficult because there is no direct way of estimating the heating terms from chromospheric observations. However, through the study of magnetic fields it is possible to put some constraints on the heating terms. Magnetic fields are, indeed, a key ingredient to explain the topology and flows in the chromosphere: they regulate the dynamics, the energy balance and the atmospheric structures of this layer of the solar atmosphere. We studied the topology of magnetic fields in plage regions, by developing a new version of the well-known weak field approximation (WFA), the spatially-regularised WFA. We, then, focused on the calculation of the radiative losses in a plage region. Our results show that radiative losses in the upper chromosphere form a relatively homogeneous patch that covers the entire plage region. The time analysis shows that in all pixels, the net radiative losses can be split in a periodic component and a static (or very slowly evolving) component. We expand our study to a different type of target, loop structures in active regions. Understand how the magnetic field is connected to loop structures can help to identify the heating mechanisms that are playing a role in these type of active regions. The magnetic field structures is indeed deeply related to the processes that could be heating the chromosphere, like magnetoacoustic waves and Alfven waves dissipation. Thanks! Eliot and Kris Eliot Ayache is inviting you to a scheduled Zoom meeting. Topic: Astronomy Department Seminar Roberta Morosin Time: Sep 2, 2022 10:30 AM Stockholm Join Zoom Meeting https://stockholmuniversity.zoom.us/j/63359279960 Meeting ID: 633 5927 9960 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Sep 5 11:02:36 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 5 Sep 2022 09:02:36 +0000 Subject: [Astronomy seminar] Astronomy departmental seminar - Friday, Sept 9th - Gregor Traven Message-ID: The next SU astronomy departmental seminar will take place on Friday September 9th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. --------------------------------------------------------------------------------------------------------------------------------- Speaker: Gregor Traven - University of Ljubljana Title: Machine learning in stellar physics Abstract: I will try to present, in a heavily biased way, a broader picture of what machine learning is and how it can help us in extracting new knowledge from astronomical data. The approach of using ML techniques has become important in recent times as we welcome the flood of big data in almost every field of research, but it is important to know which methods work well and for which purpose, so I will describe some basics and present some applications of both unsupervised and supervised techniques applied to selected astronomical subjects. At the end we'll also have a look into an interesting and novel approach of data augmentation with GAN and how it could help in analysis of stellar spectra. --------------------------------------------------------------------------------------------------------------------------------- We look forward to seeing many of you there. Thanks! Kris and Eliot Topic: Astronomy Department Seminar Gregor Traven Time: Sept 9, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Sep 9 10:16:00 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 9 Sep 2022 08:16:00 +0000 Subject: [Astronomy seminar] Seminar today in FC 61 - Gregor Traven Message-ID: Reminder of the seminar happening today in 15 minutes at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. --------------------------------------------------------------------------------------------------------------------------------- Speaker: Gregor Traven - University of Ljubljana Title: Machine learning in stellar physics Abstract: I will try to present, in a heavily biased way, a broader picture of what machine learning is and how it can help us in extracting new knowledge from astronomical data. The approach of using ML techniques has become important in recent times as we welcome the flood of big data in almost every field of research, but it is important to know which methods work well and for which purpose, so I will describe some basics and present some applications of both unsupervised and supervised techniques applied to selected astronomical subjects. At the end we'll also have a look into an interesting and novel approach of data augmentation with GAN and how it could help in analysis of stellar spectra. --------------------------------------------------------------------------------------------------------------------------------- See you soon! Kris and Eliot Topic: Astronomy Department Seminar Gregor Traven Time: Sept 9, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Sep 12 16:42:21 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 12 Sep 2022 16:42:21 +0200 Subject: [Astronomy seminar] Astro department seminar - Friday, Sept 16th - Avishai Gilkis Message-ID: The next SU astronomy departmental seminar will take place on Friday September 16th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. --------------------------------------------------------------------------------------------------------------------------------- Speaker: Avishai Gilkis - Tel Aviv University Title: Uncertainty in envelope removal of core-collapse supernova progenitors Abstract: The theoretical modeling of massive star evolution is riddled with uncertainties. Two such unresolved aspects are mass loss by stellar winds and mixing in stellar interiors. In my talk I will discuss the implications of these uncertainties on reconciling theory with observations of massive stellar endpoints. In the first part I will present the role of winds for progenitors of stripped-envelope supernovae. While it is commonly assumed that binary interaction removes the hydrogen envelope, the assumed post-interaction mass-loss rate is crucial for the resulting supernova type. I will show how we assess the hydrogen mass in stripped-envelope supernova progenitors by comparing pre-supernova photometry with evolution models. In the second part of the talk I will focus on the lack of observed cool and very luminous supergiant stars, an unexplained phenomenon termed the “Humphreys-Davidson Limit”, which is in contrast to simulations of evolved massive stars. I will show how enhanced mixing above convective cores can aid in removing the hydrogen envelope and ease the tension between theory and observations for such stars at the high-mass end, which are also thought to be the progenitors of merging black holes. --------------------------------------------------------------------------------------------------------------------------------- We look forward to seeing many of you there. Thanks! Eliot and Kris Topic: Astronomy Department Seminar Gregor Traven Time: Sept 9, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Sep 16 09:41:39 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 16 Sep 2022 09:41:39 +0200 Subject: [Astronomy seminar] Astro department seminar - Friday, Sept 16th - Avishai Gilkis In-Reply-To: <8E0FCBC6-325E-4A72-A651-D4C2B79FEA94@astro.su.se> References: <8E0FCBC6-325E-4A72-A651-D4C2B79FEA94@astro.su.se> Message-ID: Kind reminder about Avishai Gilkis’ seminar in FC61 and on zoom in 50 minutes! > https://stockholmuniversity.zoom.us/s/61002076352 For external speakers we leave the zoom channel open for a little while after the questions so you can have a chat with the speaker. We will then head to Proviant for lunch at around 12. Feel free to join! Kind regards, Eliot > On 12 Sep 2022, at 16:42, Eliot Ayache wrote: > > The next SU astronomy departmental seminar will take place on Friday September 16th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. > > --------------------------------------------------------------------------------------------------------------------------------- > > Speaker: Avishai Gilkis - Tel Aviv University > Title: Uncertainty in envelope removal of core-collapse supernova progenitors > > Abstract: > The theoretical modeling of massive star evolution is riddled with uncertainties. Two such unresolved aspects are mass loss by stellar winds and mixing in stellar interiors. In my talk I will discuss the implications of these uncertainties on reconciling theory with observations of massive stellar endpoints. In the first part I will present the role of winds for progenitors of stripped-envelope supernovae. While it is commonly assumed that binary interaction removes the hydrogen envelope, the assumed post-interaction mass-loss rate is crucial for the resulting supernova type. I will show how we assess the hydrogen mass in stripped-envelope supernova progenitors by comparing pre-supernova photometry with evolution models. In the second part of the talk I will focus on the lack of observed cool and very luminous supergiant stars, an unexplained phenomenon termed the “Humphreys-Davidson Limit”, which is in contrast to simulations of evolved massive stars. I will show how enhanced mixing above convective cores can aid in removing the hydrogen envelope and ease the tension between theory and observations for such stars at the high-mass end, which are also thought to be the progenitors of merging black holes. > > --------------------------------------------------------------------------------------------------------------------------------- > > We look forward to seeing many of you there. Thanks! > > Eliot and Kris > > > Topic: Astronomy Department Seminar Gregor Traven > Time: Sept 9, 2022 10:30 AM Stockholm > > Join Zoom Meeting: > https://stockholmuniversity.zoom.us/s/61002076352 > > Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Sep 19 13:22:57 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 19 Sep 2022 13:22:57 +0200 Subject: [Astronomy seminar] Astro Department Seminar - Friday, Sept 23rd 10:30 - Mike Walmsley Message-ID: The next SU astronomy departmental seminar will take place on Friday September 23rd at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. ———————————————————————————————————————————————————————————————— Speaker: Mike Walmsley - University of Manchester Title: Galaxy Zoo in the Deep Learning Era Abstract: Deep learning is fundamental to Galaxy Zoo’s latest morphology catalogs. In this talk, I explore how we train accurate and reliable models on our volunteer labels, and consider the consequences and opportunities of such models. One obvious consequence is scale. We will shortly release detailed morphological classifications for 1.4 million nearby galaxies in the DESI Legacy Surveys - a catalog which would have been impossible with volunteers alone. But the truly new opportunity is using the models to create your own catalogs. Having already learned to answer every GZ question at once, our models are easy to adapt to new surveys and new questions. We recently exploited this to create new (and order-of-magnitude larger) catalogs of mergers in HST and ringed galaxies in DECaLS. You can answer your own morphology questions with our public code and models . Finally, we describe our very latest work on simultaneously learning from labelled and unlabelled galaxy images. Such approaches are ideally suited to Euclid and Rubin because they allow us to leverage both the millions of human labels collected over the last decade and the raw scale of unlabelled images these new surveys will produce. ———————————————————————————————————————————————————————————————— We look forward to seeing many of you there. Thanks! Eliot and Kris Topic: Astronomy Department Seminar Mike Walmsley Time: Sept 23rd, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Sep 23 09:50:44 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 23 Sep 2022 09:50:44 +0200 Subject: [Astronomy seminar] Astro Department Seminar - Friday, Sept 23rd 10:30 - Mike Walmsley In-Reply-To: <28C7560F-4105-4917-9346-C3E59DC1DC49@astro.su.se> References: <28C7560F-4105-4917-9346-C3E59DC1DC49@astro.su.se> Message-ID: Hi all, This is a kind reminder about Mike Walmsley’s seminar in 40 minutes in FC61 and on Zoom. We hope to see many of you there! Eliot and Kris > On 19 Sep 2022, at 13:22, Eliot Ayache wrote: > > The next SU astronomy departmental seminar will take place on Friday September 23rd at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. > > ———————————————————————————————————————————————————————————————— > > Speaker: Mike Walmsley - University of Manchester > Title: Galaxy Zoo in the Deep Learning Era > > Abstract: > Deep learning is fundamental to Galaxy Zoo’s latest morphology catalogs. In this talk, I explore how we train accurate and reliable models on our volunteer labels, and consider the consequences and opportunities of such models. > One obvious consequence is scale. We will shortly release detailed morphological classifications for 1.4 million nearby galaxies in the DESI Legacy Surveys - a catalog which would have been impossible with volunteers alone. But the truly new opportunity is using the models to create your own catalogs. Having already learned to answer every GZ question at once, our models are easy to adapt to new surveys and new questions. We recently exploited this to create new (and order-of-magnitude larger) catalogs of mergers in HST and ringed galaxies in DECaLS. You can answer your own morphology questions with our public code and models . > Finally, we describe our very latest work on simultaneously learning from labelled and unlabelled galaxy images. Such approaches are ideally suited to Euclid and Rubin because they allow us to leverage both the millions of human labels collected over the last decade and the raw scale of unlabelled images these new surveys will produce. > > ———————————————————————————————————————————————————————————————— > > > We look forward to seeing many of you there. Thanks! > > Eliot and Kris > > > Topic: Astronomy Department Seminar Mike Walmsley > Time: Sept 23rd, 2022 10:30 AM Stockholm > > Join Zoom Meeting: > https://stockholmuniversity.zoom.us/s/61002076352 > > Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Wed Oct 12 10:56:13 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Wed, 12 Oct 2022 10:56:13 +0200 Subject: [Astronomy seminar] Astro Department Thesis Seminar - Friday, Oct 14th 10:30 - Armin Rasekh Message-ID: The next SU astronomy departmental seminar will take place on Friday October 14th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. ———————————————————————————————————————————————————————————————— Speaker: Armin Rasekh Title: The spatial distribution of Lyman alpha from star-forming galaxies in the low redshift Universe Abstract: The Lyman-alpha (Lyα) emission is predicted to be the strongest spectral line emitted by galaxies. This emission line is regularly used to detect and observe high redshift galaxies. However, studying this spectral line is challenging. Lyα is a resonant line, meaning it interacts strongly with neutral hydrogen. Consequently, the interpretation of Lyα observations of galaxies is very complicated. Nonetheless, this complexity provides a wealth of information. One way to learn how to extract this information is to focus on low-z, Lyα emitting star-forming galaxies. The characteristics of these galaxies, such as their gas kinematics and dust, affect Lyα escape from galaxies. This is the primary motivation for the projects included in this thesis, where we focus on Lyα observations in the low-z Universe. We studied the Lyα morphology of the largest sample of nearby star-forming galaxies dedicated to Lyα studies called the Lyman Alpha Reference Sample (LARS). We investigated the Lyα light distribution and how it affects the Lyα global observables, such as Lyα luminosity, Lyα escape fraction and Lyα equivalent width. We found that the Lyα luminosity anti-correlate with the Lyα halo fraction (HF). In other words, in galaxies that are faint in Lyα, most of the Lyα luminosity originates from their Lyα halos. This result suggests that we can study faint Lyα objects by focusing on low Lyα surface brightness halos, which explains why observing faint Lyα emitters (LAEs) at high redshift is hard. Hence, the conclusions drawn from studying data that only sampled bright LAEs may have been biased. We also investigated the origin of the extended Lyα halo emission using line-of-sight kinematic information in the LARS sample. We found that the gas kinematics in the centres of galaxies plays a vital role. Depending on the intensity of the outflow of gas in the centre, we discovered that galaxies show Lyα absorption or lower Lyα flux than expected, which ultimately influences the Lyα HF. Finally, we studied a sample of six intense star-forming galaxies in the low-z Universe. Due to the strong mission of Hβ + [O III], nebular emission lines and the appearance of these galaxies, they are called green pea galaxies. We looked for any relationship between the Lyα properties and well-established diagnostics for determining whether a galaxy is a Lyman continuum emitter (LCE). We found that one of the primary LCE diagnostics -- peak separation -- correlates with HF. This result suggests that a new diagnostic for LyC escape is the Lyα halo luminosity fraction. ———————————————————————————————————————————————————————————————— We look forward to seeing many of you there. Thanks! Eliot and Kris Topic: Astronomy Department Seminar Mike Walmsley Time: Oct 14th, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Oct 14 10:16:43 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 14 Oct 2022 10:16:43 +0200 Subject: [Astronomy seminar] Astro Department Thesis Seminar - Friday, Oct 14th 10:30 - Armin Rasekh In-Reply-To: <382DF810-3562-4503-8138-9C323D9F145F@astro.su.se> References: <382DF810-3562-4503-8138-9C323D9F145F@astro.su.se> Message-ID: Hi all, This is a kind reminder about Armin’s seminar in 15min in FC61 and on zoom. See you there! Kind regards Eliot > On 12 Oct 2022, at 10:56, Eliot Ayache wrote: > > The next SU astronomy departmental seminar will take place on Friday October 14th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. > > ———————————————————————————————————————————————————————————————— > > Speaker: Armin Rasekh > Title: The spatial distribution of Lyman alpha from star-forming galaxies in the low redshift Universe > > Abstract: > The Lyman-alpha (Lyα) emission is predicted to be the strongest spectral line emitted by galaxies. This emission line is regularly used to detect and observe high redshift galaxies. However, studying this spectral line is challenging. Lyα is a resonant line, meaning it interacts strongly with neutral hydrogen. Consequently, the interpretation of Lyα observations of galaxies is very complicated. Nonetheless, this complexity provides a wealth of information. One way to learn how to extract this information is to focus on low-z, Lyα emitting star-forming galaxies. The characteristics of these galaxies, such as their gas kinematics and dust, affect Lyα escape from galaxies. This is the primary motivation for the projects included in this thesis, where we focus on Lyα observations in the low-z Universe. > > We studied the Lyα morphology of the largest sample of nearby star-forming galaxies dedicated to Lyα studies called the Lyman Alpha Reference Sample (LARS). We investigated the Lyα light distribution and how it affects the Lyα global observables, such as Lyα luminosity, Lyα escape fraction and Lyα equivalent width. We found that the Lyα luminosity anti-correlate with the Lyα halo fraction (HF). In other words, in galaxies that are faint in Lyα, most of the Lyα luminosity originates from their Lyα halos. This result suggests that we can study faint Lyα objects by focusing on low Lyα surface brightness halos, which explains why observing faint Lyα emitters (LAEs) at high redshift is hard. Hence, the conclusions drawn from studying data that only sampled bright LAEs may have been biased. > > We also investigated the origin of the extended Lyα halo emission using line-of-sight kinematic information in the LARS sample. We found that the gas kinematics in the centres of galaxies plays a vital role. Depending on the intensity of the outflow of gas in the centre, we discovered that galaxies show Lyα absorption or lower Lyα flux than expected, which ultimately influences the Lyα HF. > > Finally, we studied a sample of six intense star-forming galaxies in the low-z Universe. Due to the strong mission of Hβ + [O III], nebular emission lines and the appearance of these galaxies, they are called green pea galaxies. We looked for any relationship between the Lyα properties and well-established diagnostics for determining whether a galaxy is a Lyman continuum emitter (LCE). We found that one of the primary LCE diagnostics -- peak separation -- correlates with HF. This result suggests that a new diagnostic for LyC escape is the Lyα halo luminosity fraction. > > ———————————————————————————————————————————————————————————————— > > > We look forward to seeing many of you there. Thanks! > > Eliot and Kris > > > Topic: Astronomy Department Seminar Mike Walmsley > Time: Oct 14th, 2022 10:30 AM Stockholm > > Join Zoom Meeting: > https://stockholmuniversity.zoom.us/s/61002076352 > > Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Tue Oct 25 09:36:07 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Tue, 25 Oct 2022 09:36:07 +0200 Subject: [Astronomy seminar] Astro Department Seminar - Friday Oct 28th 10:30 - Sean Brennan Message-ID: Hi all, The next SU astronomy departmental seminar will take place on Friday October 28th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. ———————————————————————————————————————————————————————————————— Speaker: Sean Brennan Title: Unmasking the impostor: Progenitor, eruptions, and remnant of AT2016jbu Abstract: Observing the progenitor of core-collpase supernova before ther demise can often shed light of the final moments of a massive stars life. However, observations of one class of transients bring to question our understanding of how exactly a star may die, and if in fact it dies at all. AT 2016jbu is an interacting transient, with similarities to Type IIn supernovae. AT 2016jbu displays a history of erratic outbursts, lasting for at least 10 years prior to two luminous explosions, that latter of which reaches supernova-like magnitudes. The circumstellar environment of AT 2016jbu is highly asymmetrical, displaying multi peaked emission lines after maximum brightness. The historical light curve of AT 2016jbu is reminiscent of the supernova impostor, Eta carinae, proir to the great eruption in the 1840s. At late times, AT 2016jbu displays tentative signs of core-collpase. In particular the lack of nebular emission lines, and a low inferred mass of radioactive nickel. Progenitor observations reveal that AT2016jbu has exploding prematurely. We find the progenitor has the appearance of a warm 20 solar mass, yellow hypergiant, rather the expected red supergiant or wolf-rayet star. The questions thus stands, are we witnessing the death of a star or some non-terminal explosion? Using the Hubble Space Telescope, we return to the site of AT 2016jbu almost 5 years post explosion to search for a surviving star. While identifying a source at the transient site, we find the visual brightness has changed by more than 2 mags. We postulate that a surviving source has been enshrouded by dust produced in the 2016 explosion, and find an unrealistic amount is needed for a non-terminal eruption. With this, we present a possible progenitor scenario, involving a binary system, and discuss the possibility of observing the binary companion in the future. ———————————————————————————————————————————————————————————————— We look forward to seeing many of you there. Thanks! Eliot and Kris Topic: Astronomy Department Seminar Mike Walmsley Time: Oct 28th, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Oct 28 10:19:47 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 28 Oct 2022 10:19:47 +0200 Subject: [Astronomy seminar] Astro Department Seminar - Friday Oct 28th 10:30 - Sean Brennan In-Reply-To: <34AA3B05-5E7D-4C64-A07A-48A9560593B4@astro.su.se> References: <34AA3B05-5E7D-4C64-A07A-48A9560593B4@astro.su.se> Message-ID: Hi everyone, Reminder about Sean’s seminar in 10 minutes! See you there! Best, Eliot > On 25 Oct 2022, at 09:36, Eliot Ayache wrote: > > Hi all, > > The next SU astronomy departmental seminar will take place on Friday October 28th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. > > ———————————————————————————————————————————————————————————————— > > Speaker: Sean Brennan > Title: Unmasking the impostor: Progenitor, eruptions, and remnant of AT2016jbu > > Abstract: > Observing the progenitor of core-collpase supernova before ther demise can often shed light of the final moments of a massive stars life. However, observations of one class of transients bring to question our understanding of how exactly a star may die, and if in fact it dies at all. > > AT 2016jbu is an interacting transient, with similarities to Type IIn supernovae. AT 2016jbu displays a history of erratic outbursts, lasting for at least 10 years prior to two luminous explosions, that latter of which reaches supernova-like magnitudes. The circumstellar environment of AT 2016jbu is highly asymmetrical, displaying multi peaked emission lines after maximum brightness. The historical light curve of AT 2016jbu is reminiscent of the supernova impostor, Eta carinae, proir to the great eruption in the 1840s. At late times, AT 2016jbu displays tentative signs of core-collpase. In particular the lack of nebular emission lines, and a low inferred mass of radioactive nickel. Progenitor observations reveal that AT2016jbu has exploding prematurely. We find the progenitor has the appearance of a warm 20 solar mass, yellow hypergiant, rather the expected red supergiant or wolf-rayet star. The questions thus stands, are we witnessing the death of a star or some non-terminal explosion? > > Using the Hubble Space Telescope, we return to the site of AT 2016jbu almost 5 years post explosion to search for a surviving star. While identifying a source at the transient site, we find the visual brightness has changed by more than 2 mags. We postulate that a surviving source has been enshrouded by dust produced in the 2016 explosion, and find an unrealistic amount is needed for a non-terminal eruption. > > With this, we present a possible progenitor scenario, involving a binary system, and discuss the possibility of observing the binary companion in the future. > > > ———————————————————————————————————————————————————————————————— > > > We look forward to seeing many of you there. Thanks! > > Eliot and Kris > > > Topic: Astronomy Department Seminar Mike Walmsley > Time: Oct 28th, 2022 10:30 AM Stockholm > > Join Zoom Meeting: > https://stockholmuniversity.zoom.us/s/61002076352 > > Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Mon Nov 7 13:28:32 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Mon, 7 Nov 2022 12:28:32 +0000 Subject: [Astronomy seminar] Astronomy departmental seminar this Friday Nov 11th with Fernanda Nieva Message-ID: Dear all, The next SU astronomy departmental seminar will take place on Friday November 11th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. ———————————————————————————————————————————————————————————————— Speaker: Fernanda Nieva Title: OB stars as laboratories for numerous astrophysical fields Abstract: OB stars are hot, massive and luminous blue stars. They are stars of spectral types late-O or early-B and are characterized by strong hydrogen and helium lines. They are short lived and do not move far from where they formed, in loosely organized groups called OB associations. During their lifetime, they emit huge amounts of ultraviolet radiation, ionizing the surrounding interstellar gas. In the Milky Way, they are predominantly located on the spiral arms on the main plane of the Galaxy. They provide us with information about numerous fields of Astrophysics. Particularly, precise determinations of their chemical composition constitute fundamental observational constraints to stellar and galactochemical evolution, which are the standard fields where this kind of star traditionally finds its applications. What I will show in this seminar is a broader understanding of the importance of a dedicated study of OB stars that potentially can offer an independent test for several other fields. Almost half of the talk will describe how we achieve unprecedented levels of accuracy in chemical abundance determinations. These are main requirements before putting the results into a bigger context. ———————————————————————————————————————————————————————————————— https://www.albanova.se/event/astronomy-departmental-seminar-fernanda-nieva/ We look forward to seeing many of you there. Thanks! Eliot and Kris Upcoming Events: 18/11 - PhD defense of Roberta Morosin - No Seminar 25/11 - Henrik Eklund (SU) 02/12 - Sepideh Kianfar (SU) ———————————————————————————————————————————————————————————————— Topic: Astronomy Department Seminar Fernanda Nieva Time: Nov 11th, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Launch Meeting - Zoom stockholmuniversity.zoom.us Zoom is the leader in modern enterprise video communications, with an easy, reliable cloud platform for video and audio conferencing, chat, and webinars across mobile, desktop, and room systems. Zoom Rooms is the original software-based conference room solution used around the world in board, conference, huddle, and training rooms, as well as executive offices and classrooms. Founded in 2011, Zoom helps businesses and organizations bring their teams together in a frictionless environment to get more done. Zoom is a publicly traded company headquartered in San Jose, CA. Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Fri Nov 11 10:07:33 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Fri, 11 Nov 2022 09:07:33 +0000 Subject: [Astronomy seminar] Astronomy departmental seminar this Friday Nov 11th with Fernanda Nieva In-Reply-To: References: Message-ID: Dear all, This is a pleasant reminder of Maria Fernanda Nieva's seminar taking place in 20 minutes at 10:30 in the AlbaNova main building, room FC 61 on the 6th floor, and on zoom. ———————————————————————————————————————————————————————————————— Speaker: Maria Fernanda Nieva Title: OB stars as laboratories for numerous astrophysical fields Abstract: OB stars are hot, massive and luminous blue stars. They are stars of spectral types late-O or early-B and are characterized by strong hydrogen and helium lines. They are short lived and do not move far from where they formed, in loosely organized groups called OB associations. During their lifetime, they emit huge amounts of ultraviolet radiation, ionizing the surrounding interstellar gas. In the Milky Way, they are predominantly located on the spiral arms on the main plane of the Galaxy. They provide us with information about numerous fields of Astrophysics. Particularly, precise determinations of their chemical composition constitute fundamental observational constraints to stellar and galactochemical evolution, which are the standard fields where this kind of star traditionally finds its applications. What I will show in this seminar is a broader understanding of the importance of a dedicated study of OB stars that potentially can offer an independent test for several other fields. Almost half of the talk will describe how we achieve unprecedented levels of accuracy in chemical abundance determinations. These are main requirements before putting the results into a bigger context. ———————————————————————————————————————————————————————————————— https://www.albanova.se/event/astronomy-departmental-seminar-fernanda-nieva/ We look forward to seeing many of you there. Thanks! Eliot and Kris Upcoming Events: 18/11 - PhD defense of Roberta Morosin - No Seminar 25/11 - Henrik Eklund (SU) 02/12 - Sepideh Kianfar (SU) Topic: Astronomy Department Seminar Fernanda Nieva Time: Nov 11th, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Launch Meeting - Zoom stockholmuniversity.zoom.us Zoom is the leader in modern enterprise video communications, with an easy, reliable cloud platform for video and audio conferencing, chat, and webinars across mobile, desktop, and room systems. Zoom Rooms is the original software-based conference room solution used around the world in board, conference, huddle, and training rooms, as well as executive offices and classrooms. Founded in 2011, Zoom helps businesses and organizations bring their teams together in a frictionless environment to get more done. Zoom is a publicly traded company headquartered in San Jose, CA. Meeting ID: 610 0207 6352 -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Tue Nov 22 14:12:37 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Tue, 22 Nov 2022 13:12:37 +0000 Subject: [Astronomy seminar] Astronomy departmental seminar this Friday Nov 25th - Henrik Eklund Message-ID: Dear all, The next SU astronomy departmental seminar will take place on Friday November 25th at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. ———————————————————————————————————————————————————————————————— Speaker: Henrik Eklund (SU) Title: Novel radio interferometric ALMA observations of the Sun Abstract: In this talk I will present my work on observations of the Sun using radio interferometry with the Atacama Large Millimeter/sub-millimeter Array (ALMA), which offers novel high sensitivity and sub-arcsec angular resolution previously not possible in this wavelength regime. Observations at millimeter wavelengths facilitate the measurement of accurate temperatures, which is valuable towards understanding the complex physical processes taking place in the solar atmosphere. I will show the work that has been done to produce science-ready, high cadence datasets and some of their latest applications. These include identifying dynamic signatures and characterising small-scale features, developing the image reconstruction techniques to extract additional useful information from the data and using a spatio-temporal deep neural network to perform statistically based estimations and deconvolution of the data. In addition, we will look towards the future, where we at Stockholm University have the only accepted proposal for solar ALMA observations in 2022-2023 (cycle 9), which will provide the highest resolved observations at 3.0 mm to date. ———————————————————————————————————————————————————————————————— We look forward to seeing many of you there. Thanks! Eliot and Kris Upcoming Events: 02/12 - Sepideh Kianfar (SU) 09/12 - Supervisor's meeting - No Seminar 16/12 - Yutong He licentiate - No Seminar ———————————————————————————————————————————————————————————————— Topic: Astronomy Department Seminar Henrik Eklund Time: Nov 25th, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Launch Meeting - Zoom stockholmuniversity.zoom.us Zoom is the leader in modern enterprise video communications, with an easy, reliable cloud platform for video and audio conferencing, chat, and webinars across mobile, desktop, and room systems. Zoom Rooms is the original software-based conference room solution used around the world in board, conference, huddle, and training rooms, as well as executive offices and classrooms. Founded in 2011, Zoom helps businesses and organizations bring their teams together in a frictionless environment to get more done. Zoom is a publicly traded company headquartered in San Jose, CA. Meeting ID: 610 0207 6352 ________________________________ -------------- next part -------------- An HTML attachment was scrubbed... URL: From seminars-announce.astro-at-su.se at lists.su.se Thu Dec 1 14:28:37 2022 From: seminars-announce.astro-at-su.se at lists.su.se (Astronomy seminar announcements) Date: Thu, 1 Dec 2022 13:28:37 +0000 Subject: [Astronomy seminar] Astronomy departmental seminar tomorrow Friday Dec 2nd - Sepideh Kianfar (SU) Message-ID: Dear all, The next SU astronomy departmental seminar will take place on Friday December 2nd at 10:30 in room FC 61 (AlbaNova building, 6th floor) and on zoom. Please note this will be the final departmental seminar of the calendar year, as the next two Fridays there will be no seminar due to the supervisor's meeting and a licentiate defense. The seminars will resume on a weekly basis in January. ———————————————————————————————————————————————————————————————— Speaker: Sepideh Kianfar (SU) Title: Physical properties and dynamics of the bright fibrils in the solar chromosphere Abstract: The highly dynamic solar chromosphere gives rise to various fine structures that cover the solar surface. Bright fibrils are an example of those structures, and the main topic of my presentation. They appear as thin and elongated features packed in plage regions or around pores on the solar surface. They are relatively short-lived and undergo oscillations. So far, they have been observed mostly in single spectral lines with a spectral resolution larger than 1 Å. We used observations of bright fibrils with high spatial and spectral resolution in different chromospheric spectral lines that have been acquired simultaneously at the Swedish 1-m SolarTelescope (SST). These observations provided us with the chance to have a more consistent image of how the bright fibrils appear in different layers of the chromosphere, and more importantly, it has enabled us to infer their physical properties by using non-LTE inversion of the observations. Our studies showed that their bright appearance is because they have higher temperature than their surroundings in the chromosphere. Most, but not all Ca II K fibrils are also visible in the Hα and Ca II 8542 Å line cores which suggests that fibrils are not only spread out horizontally, but can also be stacked vertically. Then we used the non-LTE inversion on the time series bright fibrils to retrieve their oscillations in the line-of-sight (vertical) direction in addition to the plane-of-sky (horizontal) direction. In all the cases in our sample the fibrils oscillated in both directions. The fact that in all cases in our sample, fibrils undergo oscillations in both directions, show that the transverse wave flux based on the imaging data is too low because the contribution of the oscillation in the vertical velocity. We determined the periods and velocity amplitudes of the fibril oscillations, as well as phase differences between vertical and horizontal oscillations in the fibrils. The results are consistent with the scenario where transverse waves are excited by granular buffeting at the photospheric footpoints of the fibrils. To further investigate the fibrils and their retrieved properties, we compared our results to the MuRAM simulations of the solar atmosphere. We synthesised the spectral lines that we had acquired with the observations using a simulated snapshot and ran the non-LTE inversions on fibrillar regions of the synthesised profiles. ———————————————————————————————————————————————————————————————— We look forward to seeing many of you there. Thanks! Eliot and Kris Upcoming Events: 09/12 - Supervisor's meeting - No Seminar 16/12 - Yutong He licentiate - No Seminar ———————————————————————————————————————————————————————————————— Topic: Astronomy Department Seminar Sepideh Kianfar Time: Dec 2nd, 2022 10:30 AM Stockholm Join Zoom Meeting: https://stockholmuniversity.zoom.us/s/61002076352 Launch Meeting - Zoom stockholmuniversity.zoom.us Zoom is the leader in modern enterprise video communications, with an easy, reliable cloud platform for video and audio conferencing, chat, and webinars across mobile, desktop, and room systems. Zoom Rooms is the original software-based conference room solution used around the world in board, conference, huddle, and training rooms, as well as executive offices and classrooms. Founded in 2011, Zoom helps businesses and organizations bring their teams together in a frictionless environment to get more done. Zoom is a publicly traded company headquartered in San Jose, CA. -------------- next part -------------- An HTML attachment was scrubbed... URL: