BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:A search for the first galaxies across >0.6 deg2 of JWST imaging: 
 new evidence for a rapid decline in star-formation activity at z>12
DTSTART:20260429T103000Z
DTEND:20260429T113000Z
DTSTAMP:20260530T234800Z
UID:indico-event-18@events.gw.iucaa.in
DESCRIPTION:Speakers: Anirban Chakraborty (IUCAA\, Pune)\n\nWe present a n
 ew determination of the evolving galaxy UV luminosity function (LF) over t
 he extreme redshift range 12.5<z<18.5\, based on a wide-area search of >0.
 6 deg2 of JWST NIRCam imaging containing >150 independent sight-lines. We 
 find evidence for an accelerated decline in the UV LF\, and hence inferred
  star-formation rate density (ρSFR)\, over the ≃100Myr cosmic time inte
 rval between z=11 and z=13.5. Moreover\, based on a notable lack of galaxy
  candidates at z>14.5\, we find evidence for an even more rapid descent in
  star-formation activity towards earlier times\, with our new measurement 
 of ρSFR at z≃15.5 lying significantly below an extrapolation of the log
 -linear ρSFR(z) relation inferred from early JWST LF studies. Instead\, w
 e find that the evolution in ρSFR(z) at these very early times is better 
 described by a piece-wise log-linear relation\, in which the decline in ρ
 SFR(z) at z>12 is ≃4 times steeper than at redshifts z<12. Our observati
 onal results are consistent with a number of theoretical models of galaxy 
 evolution which have incorporated a range of treatments in an attempt to e
 xplain the prevalence of UV-bright galaxies at least out to z≃12 (e.g.\,
  increased star-formation efficiency\, stochastic star-formation histories
 \, an evolving stellar initial mass function and/or a shift towards attenu
 ation-free stellar populations). However\, our results are also entirely c
 onsistent with a relatively simple galaxy evolution model with no such adj
 ustments\, in which the rapid evolution of the dark-matter halo mass funct
 ion at early times is\, for a while\, partially masked by progressively yo
 unger stellar ages\, with the inferred epoch of first galaxy formation lyi
 ng at z≃15.\n \nLink to the paper:   https://arxiv.org/abs/2604.16666
 \n\nhttps://events.gw.iucaa.in/event/18/
LOCATION:Lecture Hall/Bhaskara-1 (IUCAA\, Pune\, India)
URL:https://events.gw.iucaa.in/event/18/
END:VEVENT
END:VCALENDAR