[Astronomy seminar] Astronomy seminar TODAY 24/01: 10:30 FC61: Emil Rivera-Thorsen

[Astronomy seminar announcements]

A reminder of today’s Astronomy seminar.

Cristina and Arjan


> On 20 Jan 2020, at 09:36, Arjan Bik <arjan.bik at astro.su.se> wrote:
> 
> Dear all,
> 
> On Friday 24th of January, we have the next Astronomy seminar in room FC61 at 10:30.
> 
> Our speaker is Emil Rivera-Thorsen (SU):
> 
> Title: A cosmic Sunburst in stunning GravLens-vision
> 
> Abstract:
> 
> Despite a growing consensus that young galaxies contributed the majority of the
> extreme-UV photons that reionized the early Universe, we still do not have a
> firm grasp on which mechanisms have allowed these photons to escape through the
> abundant galactic neutral medium and into intergalactic space.
> 
> Low neutral column densities can arise either where a hot, luminous stellar
> population has ionized a large fraction of the galactic gas, or where
> turbulence, feedback or similar effects have created pathways through the
> neutral medium along certain lines of sight in an otherwise neutral medium.
> Realistic systems are generally complicated combinations of these effects; but
> in their pure form, they define toy models which are very useful to understand
> the underlying physics.
> 
> Two years ago, our collaboration took spectra a gravtitationally lensed galaxy
> at z=2.4, which showed a theoretically predicted, but not previously observed,
> Lyman-alpha profile arising from light escaping through a narrow, channel with
> extremely low neutral column density in an otherwise opaque neutral medium, just
> like its namesake weather phenomenon gives a direct view of the sun through
> perforated clouds. Follow-up UV imaging with Hubble Space Telescope confirmed
> that ionizing Lyman-continuum photons in large amounts are pouring out from a
> very compact region, exactly where this channel was predicted to be, confirming
> that we are looking straight down the barrel of a narrow perforation of galactic
> ISM.
> 
> The galaxy is strongly gravitationally lensed by a massive foreground cluster,
> which leads to the galaxy being seen in 12 distorted copies, each magnified
> 10-30 times; adding both extra scientific opportunity and visual spectacle to
> the mix.
> 
> https://www.albanova.se/event/astronomy-seminar-emil-rivera-thorsen/ <https://www.albanova.se/event/astronomy-seminar-emil-rivera-thorsen/>
> 
> Upcoming events:
> 31/01 (Fri) @ 10:30: Jes Jorgensen (NBI)
> 07/02 (Fri) @ 10:30: John  Airy (SU Science Education)
> 14/02 (Fri) @ 10:30: Per Calissendorff (PhD seminar)
> 21/02 (Fri) @ 10:30: Beibei Liu (Lund)
> 
> Kind regards,
> Cristina & Arjan
> -------------------------------------------
> Dr. Arjan Bik
> Stockholm University
> AlbaNova University Center
> Department of Astronomy
> SE-106 91 Stockholm - Sweden
> Tel: +46 (0) 85537 8549
> https://www.su.se/english/profiles/abik <https://www.su.se/english/profiles/abik>
> -------------------------------------------
> 

-------------------------------------------
Dr. Arjan Bik
Stockholm University
AlbaNova University Center
Department of Astronomy
SE-106 91 Stockholm - Sweden
Tel: +46 (0) 85537 8549
https://www.su.se/english/profiles/abik
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