AGN Population Studies for CTA

TL;DR

The paper discusses the potential of the Cherenkov Telescope Array (CTA) to significantly advance our understanding of active galactic nuclei (AGN) populations, especially high-redshift blazars, through improved sensitivity and large sample sizes.

Contribution

It provides predictions for AGN detection rates and redshift distributions with CTA based on updated gamma-ray luminosity functions and spectral extrapolations.

Findings

CTA will detect approximately 50 blazars in 1 year and 160 in 10 years.

CTA is expected to find a blazar at redshift ~1.4.

CTA could detect a Fermi blazar at redshift 2.49.

Abstract

Following the great success of the current Imaging Atmospheric Cherenkov Telescopes, the next generation gamma-ray telescope arrays, Cherenkov Telescope Array (CTA), is being prepared. CTA will have an order of magnitude higher sensitivity and wider energy range than current instruments. Large samples of very high energy (VHE; >30 GeV) sources will be obtained with CTA. Here we discuss potential AGN population studies for the CTA era concerning the overall source counts and the statistics of high redshift sources. Based on our latest blazar gamma-ray luminosity function (GLF) model, we find that CTA will detect ~50 and ~160 blazars with 1 year and 10 years of blank field sky survey, respectively. CTA is also expected to find a blazar at z~1.4 (~20 blazars above z=1) based on the blazar GLF. Furthermore, we also examine the detectability of high redshift Fermi blazars. By extrapolating the Fermi blazars' spectra with a power-law, we find that CTA has a capability to detect a Fermi blazar at z=2.49.