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<p>On Friday, March 18th at 10:30 we have our next seminar with
David Sobral (Lancaster) speaking via Zoom</p>
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Resolving the formation and evolution of primeval galaxies: from
re-ionisation to cosmic noon</b></div>
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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.<br
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<br class="">
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.</div>
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<div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode:
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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.</div>
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<div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode:
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Chris and Carolina</div>
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<div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode:
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Usher is inviting you to a scheduled Zoom meeting.
<br>
<br>
Topic: Astronomy Department Seminar - David Sobral
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Time: Mar 18, 2022 10:30 AM Stockholm
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Join Zoom Meeting
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<a class="moz-txt-link-freetext" href="https://stockholmuniversity.zoom.us/j/64177331893?pwd=bzRRT3BjTFZtVDdnL08rdlg1VEpUQT09">https://stockholmuniversity.zoom.us/j/64177331893?pwd=bzRRT3BjTFZtVDdnL08rdlg1VEpUQT09</a>
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Meeting ID: 641 7733 1893
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Passcode: eSPORdIpAR
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