The luminosity function of TeV-emitting BL Lacs: observations of an HBL sample with VERITAS

TL;DR

This study uses VERITAS observations of a carefully selected HBL sample to better understand the luminosity function of TeV-emitting BL Lacs, aiming to reduce observational biases and improve knowledge of their contribution to cosmic backgrounds.

Contribution

The paper presents a new unbiased observational program targeting 36 HBLs to accurately measure their TeV fluxes and derive the luminosity function, addressing previous biases in TeV blazar studies.

Findings

Sample of 36 HBLs observed with VERITAS

Measurements aim to minimize flux state biases

Potential to accurately determine TeV HBL luminosity function

Abstract

High-frequency-peaked BL Lacs (HBLs) dominate the extragalactic TeV sky, with more than 50 objects detected by the current generation of TeV observatories. Still, the properties of TeV-emitting HBLs as a population are poorly understood due to biases introduced by the observing strategies of Cherenkov Telescopes, limiting our ability to estimate the potential contribution of TeV blazars to the diffuse neutrino, gamma-ray, and cosmic-ray background as well as their role in the late-stage evolution of active galactic nuclei. The VERITAS telescope array has designed a program to quantify and minimize observational biases by selecting a sample of 36 HBLs and measuring their TeV flux at times that are not weighted towards high-flux states. Such a survey could form the basis for a measurement of the luminosity function of TeV-emitting HBLs.