[Astronomy seminar] Astronomy Department Seminar - March 14th David Sobral

[Astronomy seminar announcements]

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
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