<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">
<span style="font-size: 14px;" class="">Hi All,</span>
<div class=""><span style="font-size: 14px;" class=""><br class="">
</span></div>
<div class=""><span style="font-size: 14px;" class="">Here is a reminder that our PhD seminar is in 45 mins! </span></div>
<div class=""><span style="font-size: 14px;" class=""><br class="">
</span></div>
<div class=""><span style="font-size: 14px;" class="">
<div class="">Join Zoom Meeting</div>
<div class=""><a href="https://stockholmuniversity.zoom.us/j/66960083119" class="">https://stockholmuniversity.zoom.us/j/66960083119</a></div>
<div class=""><br class="">
</div>
</span></div>
<div class=""><span style="font-size: 14px;" class="">See you soon,</span></div>
<div class=""><span style="font-size: 14px;" class="">Matthias & Janet</span></div>
<div class=""><span style="font-size: 14px;" class=""><br class="">
</span>
<div><span style="font-size: 14px;" class=""><br class="">
</span>
<blockquote type="cite" class="">
<div class=""><span style="font-size: 14px;" class="">On 24 May 2021, at 21:37, Janet Ting-Wan Chen <<a href="mailto:janet.chen@astro.su.se" class="">janet.chen@astro.su.se</a>> wrote:</span></div>
<span style="font-size: 14px;" class=""><br class="Apple-interchange-newline">
</span>
<div class="">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">
<div class=""><span class="" style="font-size: 14px;">Dear all,</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">On Friday May 28 at 10:30, we will have the next Astronomy PhD Seminar, remotely via zoom.</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Our speaker is Johannes Puschnig from the Stockholm University.</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Title: Molecular gas and ionizing radiation in star-forming galaxies</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Abstract: I present the main findings of my PhD work. Using panchromatic observations ranging from the 21cm H I line in the radio regime to the extreme ultraviolet (UV), we studied ionizing radiation from
massive stars (direct and through hydrogen recombination lines) as well as the atomic and molecular gas content in 15 highly star-forming local galaxies. The results are brought into cosmological context, taking a step forward towards finding answers to the
following open questions in galaxy evolution: Which physical conditions enable galaxies to leak ionizing radiation (and power reionization)? What drives the high Lyman-alpha escape fractions observed in the early Universe? How did the massive stellar clumps
found in high redshift galaxies have possibly formed?</span></div>
<div class=""><span style="font-size: 14px;" class=""><span class="">One of the galaxies we studied is Tololo 1247-232, a galaxy that leaks ionizing radiation. We argue that the Lyman continuum escape in Tololo 1247-232 is facilitated by the large amount of
ionizing radiation that is produced in the central region and then escapes from clumpy, density bounded regions. This scenario may also explain how early galaxies at z>6 have powered cosmic reionization. Additionally, we performed infrared and molecular gas
(traced by CO) observations of galaxies drawn from the "Lyman Alpha Reference Sample'' (LARS). The galaxies were selected as analogues of high-redshift galaxies. Our main discovery is a roughly linear trend between the Lyman-alpha escape fraction and the total
gas depletion time. This finding is counter-intuitive, because given the resonant scattering nature of Lyman-alpha photons, an increase in atomic gas should result in longer path lengths out of the galaxy, making photons more prone to absorption. Some other
process seems to facilitate Lyman-alpha escape. We speculate that gas accretion enhances the turbulence of the cold gas and shifts the Lyman-alpha photons out of resonance. This scenario would naturally explain elevated Lyman-alpha escape fractions during
the phases in cosmic history when galaxies were still accretion-dominated (at high-z) rather than defined by gas depletion. Finally, we present high-resolution interferometric observations of a single galaxy, LARS 8. The galaxy is a proto-typical analogue
of normal star-forming galaxies at z~1-2, i.e. it is massive, has a large gas fraction, is rotationally supported and its morphology is dominated by massive clumps. We show that these clumps are the result of an extremely gravitationally unstable gas disc.
Large scale instabilities are found across the whole extent of the rotating disc, with only the innermost </span><span class="">500pc being stabilized by its bulgelike structure. Our findings prove that gravitational instabilities may play a significant role
in galaxy evolution, in particular at z ≃ 1-3, when galaxies are characterized by massive clumps.</span></span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><a href="https://www.albanova.se/event/johannes_puschnig/" class="" style="font-size: 14px;">https://www.albanova.se/event/johannes_puschnig/</a></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">We will have the colloquium using zoom. You will find the invitation at the end of this email.</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Some guidelines:</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">1) Join the session with your microphone muted.</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">2) When you have a question, press the “raise hand button” and wait till you are asked to ask your question. </span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">3) The session will be online from 10:20, please join at least a few minutes early as we would like to start 10:30 sharp.</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">We hope to see all of you there!</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Matthias & Janet</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Upcoming events: </span></div>
<div class=""><span class="" style="font-size: 14px;">4/6: Deborah Baker (UCL)</span></div>
<div class=""><span class="" style="font-size: 14px;">11/6: Nushkia Chamba (SU)</span></div>
<div class=""><span class="" style="font-size: 14px;">End of this semester's seminar </span></div>
<div class=""><span class="" style="font-size: 14px;">===================================================</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Janet Ting-Wan Chen is inviting you to a scheduled Zoom meeting.</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Topic: Astronomy Seminar Johannes Puschnig</span></div>
<div class=""><span class="" style="font-size: 14px;">Time: May 28, 2021 10:30 AM Stockholm</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Join Zoom Meeting</span></div>
<div class=""><a href="https://stockholmuniversity.zoom.us/j/66960083119" class="" style="font-size: 14px;">https://stockholmuniversity.zoom.us/j/66960083119</a></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Meeting ID: 669 6008 3119</span></div>
<div class=""><span class="" style="font-size: 14px;">One tap mobile</span></div>
<div class=""><span class="" style="font-size: 14px;">+46850539728,,66960083119# Sweden</span></div>
<div class=""><span class="" style="font-size: 14px;">+46844682488,,66960083119# Sweden</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Dial by your location</span></div>
<div class=""><span class="" style="font-size: 14px;"> +46 850 539 728 Sweden</span></div>
<div class=""><span class="" style="font-size: 14px;"> +46 8 4468 2488 Sweden</span></div>
<div class=""><span class="" style="font-size: 14px;"> +46 8 5016 3827 Sweden</span></div>
<div class=""><span class="" style="font-size: 14px;"> +46 8 5050 0828 Sweden</span></div>
<div class=""><span class="" style="font-size: 14px;"> +46 8 5050 0829 Sweden</span></div>
<div class=""><span class="" style="font-size: 14px;"> +46 8 5052 0017 Sweden</span></div>
<div class=""><span class="" style="font-size: 14px;">Meeting ID: 669 6008 3119</span></div>
<div class=""><span class="" style="font-size: 14px;">Find your local number: <a href="https://stockholmuniversity.zoom.us/u/ccHMlLos03" class="">https://stockholmuniversity.zoom.us/u/ccHMlLos03</a></span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Join by SIP</span></div>
<div class=""><span class="" style="font-size: 14px;"><a href="mailto:66960083119@109.105.112.236" class="">66960083119@109.105.112.236</a></span></div>
<div class=""><span class="" style="font-size: 14px;"><a href="mailto:66960083119@109.105.112.235" class="">66960083119@109.105.112.235</a></span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Join by H.323</span></div>
<div class=""><span class="" style="font-size: 14px;">109.105.112.236</span></div>
<div class=""><span class="" style="font-size: 14px;">109.105.112.235</span></div>
<div class=""><span class="" style="font-size: 14px;">Meeting ID: 669 6008 3119</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;">Join by Skype for Business</span></div>
<div class=""><a href="https://stockholmuniversity.zoom.us/skype/66960083119" class="" style="font-size: 14px;">https://stockholmuniversity.zoom.us/skype/66960083119</a></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span class="" style="font-size: 14px;"><br class="">
</span></div>
<div class=""><span style="font-size: 14px;" class=""><br class="">
</span></div>
</div>
</div>
</blockquote>
</div>
<br class="">
</div>
</body>
</html>