Catching blazars in the act! GLAST triggers for TeV observation of blazars

TL;DR

This paper discusses strategies for using GLAST (now Fermi) triggers to identify blazars in active states suitable for TeV observations, aiding in understanding their emission mechanisms.

Contribution

It proposes a method to select blazars likely detectable at TeV energies based on extrapolations of EGRET spectra and GLAST sensitivity, optimizing multi-wavelength observations.

Findings

Identification of blazar activity states suitable for TeV detection

Threshold flux estimates for GLAST to TeV observability

Extrapolation models for predicting TeV brightness of blazars

Abstract

The double humped SED (Spectral Energy Distribution) of blazars, and their flaring phenomena can be explained by various leptonic and hadronic models. However, accurate modeling of the high frequency component and clear identification of the correct emission mechanism would require simultaneous measurements in both the MeV-GeV band and the TeV band. Due to the differences in the sensitivity and the field of view of the instruments required to do these measurements, it is essential to identify active states of blazars likely to be detected with TeV instruments. Using a reasonable intergalactic attenuation model, various extrapolations of the EGRET spectra, as a proxy for GLAST (Gamma-ray Large Area Space Telescope) measurements, are made into TeV energies for selecting EGRET blazars expected to be VHE-bright. Furthermore, estimates of the threshold fluxes at GLAST energies are provided, at which sources are expected to be detectable at TeV energies, with Cherenkov telescopes like HESS, MAGIC or VERITAS.