The long-term centimeter variability of active galactic nuclei: A new relation between variability timescale and accretion rate

Abstract

We study the long-term ($\approx$30 years) radio variability of 43 radio bright AGNs by exploiting the data base of the University of Michigan Radio Astronomy Observatory (UMRAO) monitoring program. We model the periodograms (temporal power spectra) of the observed lightcurves as simple power-law noise (red noise, spectral power $P(f)\propto f^{-\beta }$) using Monte Carlo simulations, taking into account windowing effects (red-noise leak, aliasing). The power spectra of 39 (out of 43) sources are in good agreement with the models, yielding a range in power spectral index ($\beta$) from $\approx$1 to $\approx$3. We fit a Gaussian function to each flare in a given lightcurve to obtain the flare duration. We discover a correlation between $\beta$ and the median duration of the flares. We use the derivative of a lightcurve to obtain a characteristic variability timescale which does not depend on the assumed functional form of the flares, incomplete fitting, and so on. We find that, once the effects of relativistic Doppler boosting are corrected for, the variability timescales of our sources are proportional to the accretion rate to the power of $0.25\pm 0.03$ over five orders of magnitude in accretion rate, regardless of source type. We further find that modeling the periodograms of four of our sources requires the assumption of broken powerlaw spectra. From simulating lightcurves as superpositions of exponential flares we conclude that strong overlap of flares leads to featureless simple power-law periodograms of AGNs at radio wavelengths in most cases.

arXiv comment23 pages, 20 figures, 3 tables; to appear in ApJ (submitted 2016 July 26; accepted 2016 November 10)

References in corpus (94)

• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• A Relationship Between Nuclear Black Hole Mass and Galaxy Velocity Dispersion
• The slope of the black-hole mass versus velocity dispersion correlation
• Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships
• Efficient Generation of Jets from Magnetically Arrested Accretion on a Rapidly Spinning Black Hole
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• Supermassive Black Holes in Galactic Nuclei: Past, Present and Future Research
• The Relationship Between Luminosity and Broad-Line Region Size in Active Galactic Nuclei
• AGN Black Hole Masses and Bolometric Luminosities
• Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations?
• Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Jet Kinematics from Bimonthly Monitoring with the Very Long Baseline Array
• Active Galactic Nuclei as scaled-up Galactic black holes
• Turbulent, Extreme Multi-Zone Model for Simulating Flux and Polarization Variability in Blazars
• The M(BH)-Sigma Relation for Supermassive Black Holes
• Constraints on the Physical Parameters of TeV Blazars
• Probing the Inner Jet of the Quasar PKS 1510-089 with Multi-waveband Monitoring during Strong Gamma-ray Activity
• Measuring the broadband power spectra of active galactic nuclei with RXTE
• MOJAVE. X. Parsec-Scale Jet Orientation Variations and Superluminal Motion in AGN
• The power of relativistic jets is larger than the luminosity of their accretion disks
• Doppler factors, Lorentz factors and viewing angles for quasars, BL Lacertae objects and radio galaxies
• Measuring the black hole masses of high redshift quasars
• The supermassive black hole of M87 and the kinematics of its associated gaseous disk
• Mass Functions of the Active Black Holes in Distant Quasars from the Large Bright Quasar Survey, the Bright Quasar Survey, and the Color-Selected Sample of the SDSS Fall Equatorial Stripe
• A simple test for periodic signals in red noise
• Combined Long and Short Timescale X-ray Variability of NGC4051 with RXTE and XMM-Newton
• Gamma-ray Light Curves and Variability of Bright Fermi-Detected Blazars
• The transition between BL Lac objects and Flat Spectrum Radio Quasars
• MOJAVE: Monitoring of Jets in AGN with VLBA Experiments - I. First-Epoch 15 GHz Linear Polarization Images
• The black-hole masses of Seyfert galaxies and quasars
• Jets and accretion processes in Active Galactic Nuclei: further clues
• Polarization and structure of relativistic parsec-scale AGN jets
• The Fermi blazars divide
• Relativistic beaming and gamma-ray brightness of blazars
• Flaring Behavior of the Quasar 3C~454.3 across the Electromagnetic Spectrum
• A Bayesian test for periodic signals in red noise
• Correlated Multi-Waveband Variability in the Blazar 3C~279 from 1996 to 2007
• X-Ray Spectral Variability Signatures of Flares in BL Lac Objects
• Black hole mass estimate for a sample of radio-loud narrow-line Seyfert 1 galaxies
• The jet power, radio loudness and black hole mass in radio loud AGNs
• Time-correlation between the radio and gamma-ray activity in blazars and the production site of the gamma-ray emission
• On the use of structure functions to study blazar variability: caveats and problems
• A method for the estimation of the significance of cross-correlations in unevenly sampled red-noise time series
• A near-IR variability study of the Galactic black hole: a red noise source with no detected periodicity
• A Stochastic Model for the Luminosity Fluctuations of Accreting Black Holes
• The Blazar Main Sequence
• Similarity of the Optical-IR and Gamma-Ray Time Variability of Fermi Blazars
• The black hole mass of low redshift radiogalaxies
• On the masses of black-holes in radio-loud quasars
• The Lick AGN Monitoring Project: Recalibrating Single-Epoch Virial Black Hole Mass Estimates
• Jet and accretion power in the most powerful Fermi blazars
• Disk-Jet Connection in the Radio Galaxy 3C 120
• Statistical analyses of long-term variability of AGN at high radio frequencies
• Radio to gamma-ray variability study of blazar S5 0716+714
• Connection between the Accretion Disk and Jet in the Radio Galaxy 3C 111
• The Black Hole Masses and Host Galaxies of BL Lac Objects
• The nature of the molecular gas system in the core of NGC 1275
• The Fractal Dimension of Projected Clouds
• Three dimensional magnetic field structure of six parsec-scale active galactic nuclei jets
• Pearson-Readhead Survey Sources II: The Longterm Centimeter-band Total Flux and Linear Polarization Properties of a Complete Radio Sample
• The Connection Between Jets, Accretion Disks, and Black Hole Mass in Blazars
• Quasi-Periodic Oscillations of ~ 15 minutes in the Optical Light Curve of the BL Lac S5 0716+714
• A multifrequency analysis of radio variability of blazars
• Stochastic Modeling of the Fermi/LAT Gamma-ray Blazar Variability
• Long-term radio variability of AGN: flare characteristics
• The black hole mass of BL Lac objects from the stellar velocity dispersion of the host galaxy
• Studies of the Jet in BL Lacertae I. Recollimation Shock and Moving Emission Features
• Nearly Periodic Fluctuations in the Long Term X-ray Light Curves of the Blazars AO 0235+164 and 1ES 2321+419
• Catching the radio flare in CTA 102 I. Light curve analysis
• Multifrequency VLBA Monitoring of 3C 273 during the INTEGRAL Campaign in 2003 - I. Kinematics of the Parsec Scale Jet from 43 GHz Data
• Multiwavelength Intraday Variability of the BL Lac S5 0716+714
• Observational evidence for the link between the variable optical continuum and the subparsec-scale jet of the radio galaxy 3C 390.3
• Locating the gamma-ray emission site in Fermi/LAT blazars from correlation analysis between 37 GHz radio and gamma-ray light curves
• Quasi-Periodic Oscillation in Seyfert galaxies: Significance levels. The Case of Mrk 766
• Fourier Analysis of Blazar Variability
• Host galaxies and black hole masses of low and high luminosity radio loud active nuclei
• The fractal dimension of star-forming regions at different spatial scales in M33
• Relativistic plasma as the dominant source of the optical continuum emission in the broad-line radio galaxy 3C 120
• VLBA monitoring of Mrk 421 at 15 GHz and 24 GHz during 2011
• Simultaneous Ultraviolet and Optical Emission-line Profiles of Quasars: Implications for Black Hole Mass Determination
• MAXI investigation into the longterm X-ray variability from the very-high-energy gamma-ray blazar Mrk 421
• Broad-line region structure and kinematics in the radio galaxy 3C 120
• Long-term variability of radio-bright BL Lacertae objects
• Black hole masses and the Fundamental Plane of BL Lac objects
• Polarization structure in the core of 1803+784: a signature of recollimation shocks?
• Population statistics of beamed sources. II: Evaluation of Doppler factor estimates
• The long-term millimeter activity of active galactic nuclei
• Locating the gamma-ray emission site in Fermi/LAT blazars. II Multifrequency correlations
• Radio Variability and Random Walk Noise Properties of Four Blazars
• Fourier Analysis of Blazar Variability: Klein-Nishina Effects and the Jet Scattering Environment
• Frequency-dependent time delays for strong outbursts in four blazars from the Metsahovi and UMRAO monitoring databases
• The First Hard X-Ray Power Spectral Density Functions of AGN
• Frequency dependent core shifts and parameter estimation for the blazar 3C 454.3

Cited by in corpus (18)

• Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales
• Jet collimation and acceleration in the giant radio galaxy NGC 315
• Characteristic Variability Timescales in the Gamma-ray Power Spectra of Blazars
• Robust Identification of Active Galactic Nuclei through HST Optical Variability in GOODS-S: Comparison with the X-ray and mid-IR Selected Samples
• Revealing the Nature of Blazar Radio Cores through Multi-Frequency Polarization Observations with the Korean VLBI Network
• Broad line region and black hole mass of PKS 1510-089 from spectroscopic reverberation mapping
• Multiwavelength variability power spectrum analysis of the blazars 3C 279 and PKS 1510-089 on multiple timescales
• Ejection of Double knots from the radio core of PKS 1510--089 during the strong gamma-ray flares in 2015
• A persistent double nuclear structure in 3C 84
• Evidence for a toroidal magnetic field in the core of 3C 84
• The properties of magnetised cold filaments in a cool-core galaxy cluster
• Optical variability power spectrum analysis of blazar sources on intranight timescales
• Jet Collimation and Acceleration in the Flat Spectrum Radio Quasar 1928+738
• Probing the disc-jet coupling in S4 0954+65, PKS 0903-57, & 4C +01.02 with $\gamma$-rays
• Multi-wavelength temporal variability of the blazar PKS 1510-089
• Archival VLBA observations of the Cygnus A Nuclear Radio Transient (Cyg A-2) Strengthen the Tidal Disruption Event Interpretation
• Gamma-ray flares from the jet of the blazar CTA 102 in 2016-2018
• The physical properties of candidate neutrino-emitter blazars