Blazar Variability: A Study of Non-stationarity and the Flux-RMS Relation

Abstract

We analyze X-ray light curves of the blazars Mrk 421, PKS 2155-304, and 3C 273 using observations by the Soft X-ray Telescope on board AstroSat and archival XMM-Newton data. We use light curves of length 30-90 ks each from 3-4 epochs for all three blazars. We apply the autoregressive integrated moving average (ARIMA) model which indicates the variability is consistent with short memory processes for most of the epochs. We show that the power spectral density (PSD) of the X-ray variability of the individual blazars are consistent within uncertainties across the epochs. This implies that the construction of broadband PSD using light curves from different epochs is accurate. However, using certain properties of the variance of the light curves and its segments, we show that the blazars exhibit hints of non-stationarity beyond that due to their characteristic red noise nature in some of those observations. We find a linear relationship between the root-mean-squared amplitude of variability at shorter timescales and the mean flux level at longer timescales for light curves of Mrk 421 across epochs separated by decades as well as light curves spanning 5 days and $\sim$10 yr. The presence of flux-rms relation over very different timescales may imply that, similar to the X-ray binaries and Seyfert galaxies, longer and shorter timescale variability are connected in blazars.

arXiv comment12 pages, 4 figures. Accepted for publication in the Astrophysical Journal

References in corpus (41)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• X-ray Properties of Black-Hole Binaries
• On characterising the variability properties of X-ray light curves from active galaxies
• Active Galactic Nuclei as scaled-up Galactic black holes
• Turbulent, Extreme Multi-Zone Model for Simulating Flux and Polarization Variability in Blazars
• Non-linear X-ray variability in X-ray binaries and active galaxies
• Measuring the broadband power spectra of active galactic nuclei with RXTE
• Combined Long and Short Timescale X-ray Variability of NGC4051 with RXTE and XMM-Newton
• The flux-dependent amplitude of broadband noise variability in X-ray binaries and active galaxies
• Flexible and Scalable Methods for Quantifying Stochastic Variability in the Era of Massive Time-Domain Astronomical Data Sets
• Correlated Multi-Waveband Variability in the Blazar 3C~279 from 1996 to 2007
• Fermi Large Area Telescope View of the Core of the Radio Galaxy Centaurus A
• A Stochastic Model for the Luminosity Fluctuations of Accreting Black Holes
• Similarity of the Optical-IR and Gamma-Ray Time Variability of Fermi Blazars
• Driving extreme variability: The evolving corona and evidence for jet launching in Markarian 335
• Characteristic X-ray Variability of TeV Blazars: Probing the Link between the Jet and the Central Engine
• Disk-Jet Connection in the Radio Galaxy 3C 120
• Connection between the Accretion Disk and Jet in the Radio Galaxy 3C 111
• Long Term Variability of Cyg X-1, II. The rms-Flux Relation
• A dynamic black hole corona in an active galaxy through X-ray reverberation mapping
• Autoregressive Times Series Methods for Time Domain Astronomy
• On the distribution of particle acceleration sites in plasmoid-dominated relativistic magnetic reconnection
• Time-dependent Radiation Transfer in the Internal Shock Model Scenario for Blazar Jets
• The remarkable X-ray variability of IRAS 13224-3809 I: The variability process
• The rapid X-ray variability of NGC 4051
• The Ubiquity of the rms-flux relation in Black Hole X-ray Binaries
• XMM-Newton View of PKS 2155-304: Characterizing the X-ray Variability Properties with EPIC-PN
• Kepler observations of rapid optical variability in the BL Lac object W2R1926+42
• Lognormal variability in BL Lacertae
• A Dual Frequency, Multi-Year Monitoring Program of Compact Radio Sources
• Gamma-ray Flux Distribution and Non-linear behavior of Four LAT Bright AGNs
• The flux distribution of individual blazars as a key to understand the dynamics of particle acceleration
• A jet model for the fast IR variability of the black hole X-ray binary GX 339-4
• Long-term study of Mkn 421 with the HAGAR Array of Telescopes
• Characteristic Variability Timescales in the Gamma-ray Power Spectra of Blazars
• Studies in Astronomical Time Series Analysis: VII. An Enquiry Concerning Non-Linearity, the RMS-Mean Flux Relation, and log-Normal Flux Distributions
• Possible Accretion Disk Origin of the Emission Variability of a Blazar Jet
• AutoRegressive Planet Search: Methodology
• Seed Photon Fields of Blazars in the Internal Shock Scenario
• The Accretion Disc-Jet Connection in Blazars
• AstroSat - a multi-wavelength astronomy satellite

Cited by in corpus (13)

• Multiwavelength variability power spectrum analysis of the blazars 3C 279 and PKS 1510-089 on multiple timescales
• The hot circumgalactic medium of the Milky-Way: new insights from XMM-Newton observations
• Optical Quasi-periodic Oscillations in the TESS light curves of three blazars
• Optical variability power spectrum analysis of blazar sources on intranight timescales
• Deterministic Aspect of the $\gamma$-ray Variability in Blazars
• Probing the disc-jet coupling in S4 0954+65, PKS 0903-57, & 4C +01.02 with $\gamma$-rays
• Short-term X-ray Variability during Different Activity Phases of Blazars S5 0716+714 and PKS 2155-304
• Gamma-ray Blazar variability: New statistical methods of time-flux distributions
• Multi-frequency Variability Study of Flat-Spectrum Radio Quasar PKS 0346-27
• On the origin of multifrequency temporal and spectral variability in Ton 599
• State Space Modelling for detecting and characterising Gravitational Waves afterglows
• Minijets and Broken Stationarity in a Blazar : Novel Insights into the Origin of $\gamma$-ray Variability in CTA 102
• NICER Perspective on TeV Blazar Mrk~421: X-ray Variability and Particle Acceleration