The Search for Ionizing Radiation at High Redshift

by Prof. Alice Shapley (UCLA)

Thursday Oct 21, 2021, 3:30 PM → 4:30 PM Pacific/Honolulu

Determining the contribution of galaxies to the reionization of 
the universe is a fundamental goal for studies of the 
intergalactic medium (IGM), and galaxy formation and evolution. 
A direct measurement of ionizing Lyman-continuum radiation 
escaping from galaxies is not possible at the epoch of 
reionization, due to the high optical depth of the IGM, and 
therefore observations of this process at slightly lower 
redshift are crucial for understanding what happens at z>6. 
For the past several years, we have been attempting direct 
imaging and spectroscopic observations of escaping ionizing 
radiation at z~3, using both ground-based and HST data. These 
observations have uncovered many possible sources of Lyman 
continuum radiation, but also reveal the challenges associated 
with low-redshift contamination. We highlight the current 
state of the field and promising upcoming methods for 
determining f_esc, the escape fraction of ionizing radiation.

 

Video - Dr. A Shapley