Flare Duty Cycle and Energy Fraction of Gamma-Ray Blazars and Implications for High-Energy Neutrinos

Abstract

According to the three-sigma high-energy neutrino source association of IC-170922A with a gamma-ray flare of a blazar TXS 0506+056, it is expected that gamma-ray flares of blazars would be ideal periods for high-energy neutrino emission. In this work, we present our findings from analyzing 145 gamma-ray bright blazars observed by Fermi-LAT to determine the contribution of gamma-ray blazar flares to high-energy neutrino emission. We derived the flare duty cycle and energy fraction from the weekly binned light curves of these blazars, identifying a significant difference in flare duty cycles between FSRQs and BL Lacs at a significance level of 5 %. We also estimated the neutrino energy flux of each gamma-ray flare using a general scaling relation for the neutrino and gamma-ray luminosities, L? ? (L?)? with ? = 1.0 - 2.0, normalized to the quiescent gamma-ray and X-ray flux of each blazar. Lastly we present the upper-limit contribution of gamma-ray blazars to the isotropic diffuse neutrino flux.