Gamma-ray Flux Distribution and Non-linear behavior of Four LAT Bright AGNs

Abstract

We present a statistical characterization of the $\gamma$-ray emission from the four \emph{Fermi}-LAT sources: FR I radio galaxy NGC 1275, BL Lac Mrk 421, FSRQs B2 1520+31 and PKS 1510-089 detected almost continuously over a time integration of 3-days between August 2008 - October 2015. The observed flux variation is large, spanning $\gtrsim 2$ orders of magnitude between the extremes except for Mrk~421. We compute the flux distributions and compare with Gaussian and lognormal ones. We find that the 3 blazars have distribution consistent with a lognormal, suggesting that the variability is of a non-linear, multiplicative nature. This is further supported by the computation of the flux-rms relation, which is observed to be linear for the 3 blazars. However, for NGC 1275, the distribution does not seem to be represented either by a lognormal or a Gaussian, while its flux-rms relation is still found to be linear. We also compute the power spectra, which suggest the presence of a break, but are consistent with typical scale-free power-law shot noise. The results are broadly consistent with the statistical properties of the magnetic reconnection powered minijets-in-a-jet model. We discuss other possible scenarios and implications of these observations on jet processes and connections with the central engine.

15 Pages, 5 Figures, 3 Tables, accepted in the ApJ

References in corpus (21)

• Fast TeV variability in blazars: jets in a jet
• The power of relativistic jets is larger than the luminosity of their accretion disks
• Accretion states and radio loudness in Active Galactic Nuclei: analogies with X-ray binaries
• Rapid variability in TeV blazars: the case of PKS 2155-304
• Global Energetics of Solar Flares: V. Energy Closure in Flares and Coronal Mass Ejections
• A Magnetohydrodynamic Model for the Formation of Episodic Jets
• Black-hole jets without large-scale net magnetic flux
• Stochastic Modeling of the Fermi/LAT Gamma-ray Blazar Variability
• Fermi-LAT Observations of High-energy Behind-the-limb Solar Flares
• The minijets-in-a-jet statistical model and the RMS-flux correlation
• Lognormal variability in BL Lacertae
• A power-law break in the near-infrared power spectrum of the Galactic center black hole
• On the role of fast magnetic reconnection in accreting black hole sources
• A magnetic reconnection model for explaining the multi-wavelength emission of the microquasars Cyg X-1 and Cyg X-3
• The rms-flux relation in accreting white dwarfs: another nova-like variable and the first dwarf nova
• The Cosmic Battery in Astrophysical Accretion Disks
• A formal method for identifying distinct states of variability in time-varying sources: SgrA* as an example
• Brightest Fermi-LAT Flares of PKS 1222+216: Implications on Emission and Acceleration Processes
• On the spectral curvature of VHE blazar 1ES\,1011+496: Effect of spatial particle diffusion
• Multi-wavelength Temporal Variability of the Blazar 3C 454.3 during 2014 Activity Phase
• Similar phenomena at different scales: Black Holes, the Sun, Gamma-ray Bursts, Supernovae, Galaxies and Galaxy Clusters

Cited by in corpus (4)

• Blazar variability power spectra from radio up to TeV photon energies: Mrk 421 and PKS 2155-304
• A Multi-wavelength View of OJ 287 Activity in 2015-2017: Implications of Spectral Changes on Central-engine Models and MeV-GeV Emission Mechanism
• Probing an X-ray flare pattern in Mrk 421 induced by multiple stationary shocks: a solution to the bulk Lorentz factor crisis
• Short-term X-ray Variability during Different Activity Phases of Blazars S5 0716+714 and PKS 2155-304