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arXiv · 2005.02648

Cosmological Evolution of Flat-Spectrum Radio Quasars based on the {\it Swift}/BAT 105-month Catalog and Their Contribution to the Cosmic MeV Gamma-ray Background Radiation

Koyo Toda·Yasushi Fukazawa·Yoshiyuki Inoue
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Abstract

We present a new X-ray luminosity function of flat-spectrum radio quasars (FSRQs) utilizing the latest {\it Swift}/BAT 105-month X-ray source catalog. Contrary to previous studies of FSRQs in the X-ray band, using the luminosity-dependent density evolution model, we find that FSRQs show evolutionary peaks at $z\sim1-2$ depending on luminosities. Our result is rather consistent with the evolution of FSRQs seen in the radio and GeV bands, although the number density is a factor of 5--10 smaller. We further explore the contribution of FSRQs to the cosmic MeV gamma-ray background radiation. We find that FSRQs can explain only $\sim3$\% of the observed MeV gamma-ray background fluxes around 1 MeV, indicating other populations are required. Future MeV gamma-ray observations will be keys for understanding the origin of the MeV gamma-ray background radiation.

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Koyo Toda, Yasushi Fukazawa, Yoshiyuki Inoue. 2020-05-06. Cosmological Evolution of Flat-Spectrum Radio Quasars based on the {\it Swift}/BAT 105-month Catalog and Their Contribution to the Cosmic MeV Gamma-ray Background Radiation. https://doi.org/10.3847/1538-4357%2Fab9113

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