학술논문
Statistical properties of flux variations in blazar light curves at GeV and TeV energies
Document Type
Working Paper
Author
Wagner, Sarah M.; Burd, Paul R.; Dorner, Daniela; Mannheim, Karl; Buson, Sara; Gokus, Andrea; Madejski, Greg; Scargle, Jeffrey D.; Arbet-Engels, Axel; Baack, Dominik; Balbo, Matteo; Biland, Adrian; Bretz, Thomas; Buss, Jens; Eisenberger, Laura; Elsaesser, Dominik; Hildebrand, Dorothee; Iotov, Roman; Kalenski, Adelina; Neise, Dominik; Noethe, Maximilian; Paravac, Aleksander; Rhode, Wolfgang; Schleicher, Bernd; Sliusar, Vitalii; Walter, Roland
Source
Subject
Language
Abstract
Despite numerous detections of individual flares, the physical origin of the rapid variability observed from blazars remains uncertain. Using Bayesian blocks and the Eisenstein-Hut HOP algorithm, we characterize flux variations of high significance in the $\gamma$-ray light curves of two samples of blazars. Daily binned long-term light curves of TeV-bright blazars observed with the First G-APD Cherenkov Telescope (FACT) are compared to those of GeV-bright blazars observed with the Large Area Telescope on board the $Fermi$ Gamma-ray Space Telescope ($Fermi$-LAT). We find no evidence for systematic asymmetry of the flux variations based on the derived rise and decay time scales. Additionally, we show that the daily-binned blazar light curves can be described by an exponential stochastic Ornstein-Uhlenbeck (OU) process with parameters depending on energy. Our analysis suggests that the flux variability in both samples is a superposition of faster fluctuations. This is, for instance, challenging to explain by shock-acceleration but expected for magnetic reconnection.
Comment: for associated HOP algorithm, see https://github.com/swagner-astro/lightcurves and for associated OU algorithm, see https://github.com/PRBurd/astro-wue
Comment: for associated HOP algorithm, see https://github.com/swagner-astro/lightcurves and for associated OU algorithm, see https://github.com/PRBurd/astro-wue