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EP: Fachverband Extraterrestrische Physik

EP 15: Astrophysics: Cosmology

EP 15.3: Talk

Friday, March 24, 2023, 14:30–14:45, HSZ/0004

Modeling the extragalactic background light — •Devesh Chopra and Dieter Horns — Institut für Experimentalphysik, Universität Hamburg, Luruper Chausseee 149, D-22761 Hamburg

The Extragalactic Background Light(EBL) consists of the background light from all of the stars throughout the history of universe and hence contains a great deal of information about the evolution of galaxies from very early times up to the present. Although it is difficult to observe the EBL directly it could me modeled using various methods. Here, we present an updated model of the EBL computed directly from the global SFR.

We use the Starburst99(STScI) to generate simple stellar population spectra (SSPS) for which the IMF and metallicity are the most important parameters. The updated Cosmic Star-Formation History is used and a minimal set of assumptions are used so that it clearly connects the input physics to the output EBL. For all the input parameters of our model depending upon cosmological parameters a 737 cosmology is used but the resulting EBL intensity do not explicitly the cosmological parameters.

All the input parameters for our model are based on the most recent data hence yielding a very dependable EBL model. Our results provides a reliable lower-limit flux for the evolving Extragalactic Background Light up to redshift of 5 using minimum of parameters and assumptions. It allows a practical estimate of attenuation length for GeV-to-TeV gamma-rays. The comparison of our model with observed data points and other EBL models would be presented.