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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20211014T103000
DTEND;TZID=Atlantic/Canary:20211014T113000
UID:iactalks-1498
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/1498
CREATED:2021-10-14T10:30:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:(Re)solving Reionization with Lyman-alpha emission
DESCRIPTION:(Re)solving Reionization with Lyman-alpha emission\nDr. Jorryt 
 Matthee\n\nThe Epoch of Reionization (EoR) was the last major phase transi
 tion of  the Universe. While the timeline of reionization is increasingly 
  well-constrained, its sources remain elusive. Due to their number  densit
 y, star-forming galaxies are the likeliest candidates, but whether  the io
 nizing photon budget arose from a multitude of ultra-faint  galaxies or a 
 rarer set of bright galaxies is a key open question. The  key uncertainty 
 is the ionizing photon escape fraction (LyC Fesc), and  how this varies am
 ong galaxy properties. In my talk I will argue to  tackle this problem bas
 ed on measurements of resolved Lyman-alpha (LyA)  emission from the X-SHOO
 TER LyA survey at z=2 (XLS-z2). I will show  observational evidence that t
 he defining traits of LyC leaking galaxies  are highly ionising stellar po
 pulations, low column density gas and a  dust-free, high ionization state 
 ISM. This is evidence that galaxies  leak ionising photons (with LyC Fesc 
 20-50 %) when the hottest stars are  still shining. Motivated by these res
 ults, I will present a model of a  LyA Emitter-dominated emissivity that e
 xplains the relative flatness of  the total galaxy emissivity over z~2-8 a
 nd the reionization of the  Universe by z~6 under reasonable assumptions, 
 thus naturally accounting  for the strong evolution of the average LyC Fes
 c of the full galaxy  population between redshifts z~2-8. In a fiducial ch
 oice of model  parameters, the "disco" emissivity is dominated by a strong
  minority of  galaxies with intermediate mass (~10^8 Msun). I will conclud
 e with  proposed observational tests to further develop the LyA-anchored  
 formalism. \n \nZoom link: https://rediris.zoom.us/j/857855
 67444?pwd=ckNnYzMyQk9WRHI0MFRROWJ1QnJWdz09Meeting ID: 857 8556 7444\nPassc
 ode: 058978\n \nYouTube: https://youtu.be/iNmNi-bTKtM
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