Abstract

TeV γ-rays from distant astrophysical sources are attenuated due to electron–positron pair creation by interacting with ultraviolet/optical to infrared photons which fill the universe and are collectively known as the extragalactic background light (EBL). We model the ∼0.1–10 eV starlight component of the EBL derived from expressions for the stellar initial mass function (IMF), star formation history of the universe, and wavelength-dependent absorption of a large sample of galaxies in the local universe. These models are simultaneously fitted to the EBL data as well as to the data on the stellar luminosity density in our local universe. We find that the models with modified Salpeter A IMF together with Cole et al. or Hopkins and Beacom star formation history best represent available data. Since no dust emission is included, our calculated EBL models can be interpreted as the lower limits in the ∼0.1–1 eV range. We present simple analytic fits to the best-fit EBL model evolving with redshift. We then proceed to calculate γ-ray opacities and absorption of ∼10–300 GeV γ-rays coming from different redshifts. We discuss implications of our results for the Fermi Gamma Ray Space Telescope and ground-based Air Cherenkov Telescopes.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.