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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-4936
DTSTART:20181025T203000Z
DTEND:20181025T220000Z
DTSTAMP:20260308T045151Z
LAST-MODIFIED:20181018T191228Z
LOCATION:4421 Sterling Hall\, Coffee and cookies 3:30 PM. Talk Begins 
 at 3:45 PM
SUMMARY:How ionizing photons escape galaxies to reionize the universe\
 , Astronomy Colloquium\, John Chisholm\, University of Califormina - S
 anta Cruz
DESCRIPTION:The intergalactic medium was rapidly ionized at 6 < z < 9.
  However\, the source of cosmic reionization is hotly debated because 
 there appears to be an insufficient number of high-redshift active gal
 actic nuclei\, while neutral gas in star-forming galaxies efficiently 
 absorbs the ionizing photons produced by stars. Impending observatorie
 s (e.g.\, JWST and ELTs) aspire to determine the source of reionizatio
 n\, but the large average opacity of the high-redshift intergalactic m
 edium precludes direct observations of ionizing photons. Fortunately\,
  local analogs can be used to develop indirect diagnostics of the esca
 pe of ionizing photons. Here\, I present restframe ultraviolet observa
 tions of star-forming galaxies that emit ionizing photons at redshifts
  of 0 and 2. These observations encode details of how ionizing photons
  escape star-forming galaxies\, while also accurately predicting the e
 scape fraction of ionizing photons. These observations provide a templ
 ate for JWST and ELTs to determine the source of cosmic reionization.
URL:https://www.physics.wisc.edu/events/?id=4936
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