Detection of Lyman Continuum from z>3 galaxies in the Hubble Deep UV Legacy Survey

Abstract: Understanding the nature and properties of the sources of the reionization requires quantifying the escape fraction (f_esc) of the Lyman Continuum photons from the galaxies. The most straightforward method to measure f_esc is to detect LyC photons from galaxies directly. In recent years, several works have detected LyC sources from the nearby universe to redshift 4. However, the success rate of searches of LyC emitters at high redshift is still low. Here I will talk about our discovery of the Lyman continuum (LyC) emission from a galaxy, CDFS-6664, at z = 3.797 in a sample of Lyman break galaxies with detected [O III] emission lines. The photometric and spectroscopic data of this object enable us to make a detailed analysis of its ISM properties and sightline IGM transmission. We find that the unusually high IGM transmission of LyC photons in CDFS-6664 may be related to a foreground type-2 quasar, CDF-202, at z = 3.7, with a projected separation of 1.2 arcmin only. The quasar may have photoevaporated optically thick absorbers and enhance the transmission on the sightline of CDFS-6664.

Dr. Fangting Yuan (Associate Researcher at Shanghai Astronomical Observatory)
Zoom information: Meeting ID: 822 8287 7472 , Passcode: astroPKU , Link:
Monday, February 28, 2022 - 1:30PM to Monday, February 28, 2022 - 2:00PM