Speaker
Justin Finke
(US Naval Research Laboratory)
Description
The extragalactic background light (EBL) in the ultraviolet through optical absorbs gamma rays detectable by Fermi-LAT. We used the absorbed gamma-ray spectra of blazars to make the newest measurements of the EBL absorption optical depth. We fit these measurements with an EBL model that allows the cosmic star formation rate density (CSFRD) to vary, thus making the first accurate point-source-independent measurement of the CSFRD; that is, a measurement of the CSFRD using only gamma rays detected by the LAT. This provides strong constraints on the CSFRD at z >~5, with implications for Population III star formation.
Primary author
Justin Finke
(US Naval Research Laboratory)
Co-authors
Mr
Abhishek Desai
(Clemson University)
Alberto Dominguez
(Universidad Complutense de Madrid)
Kari Helgason
(Max Planck Institute for Astrophysics)
Prof.
Marco Ajello
(Clemson University)
Dr
Vaidehi Sharan Paliya
(Clemson University)
