Blazar Demographics with MOJAVE and GLAST

TL;DR

This paper uses VLBA observations and models to analyze blazar populations, constraining their properties and predicting their gamma-ray and radio flux distributions, with implications for the GLAST catalog.

Contribution

It provides new constraints on the Lorentz factor and luminosity functions of blazars and predicts their distribution in gamma-ray and radio flux densities.

Findings

Low-energy peaked blazars are significant in EGRET detections.

Gamma-ray weak but radio bright blazars may be obscured by Doppler beaming effects.

Predicted distributions inform future surveys and catalog completeness.

Abstract

MOJAVE is a long term VLBA program to investigate the kinematics and polarization evolution of a complete sample of 133 active galactic nuclei selected on the basis of compact, relativistically beamed jet emission at 15 GHz. By fitting to the apparent distributions of superluminal speed and jet luminosity, we can constrain the Lorentz factor distribution and intrinsic luminosity function of the radio-selected blazar parent population. These low-energy peaked blazars formed a significant fraction of all EGRET detections, and should figure prominently in the GLAST source catalog. Using simple models, we investigate the predicted distribution of GLAST blazars in the gamma-ray/radio flux density plane, and describe an extension of the MOJAVE survey that will provide extensive parsec-scale jet information in complete regions of this plane. We find that if a population of intrinsically radio bright yet gamma-ray weak blazars exists, its signal will be largely wiped out by the large gamma-ray flux scatter associated with Doppler beaming.