Locating the gamma-ray emission site in Fermi/LAT blazars from correlation analysis between 37 GHz radio and gamma-ray light curves

Abstract

We address the highly debated issue of constraining the gamma-ray emission region in blazars from cross-correlation analysis using discrete correlation function between radio and gamma-ray light curves. The significance of the correlations is evaluated using two different approaches: simulating light curves and mixed source correlations. The cross-correlation analysis yielded 26 sources with significant correlations. In most of the sources, the gamma-ray peaks lead the radio with time lags in the range +20 and +690 days, whereas in sources 1633+382 and 3C 345 we find the radio emission to lead the gamma rays by -15 and -40 days, respectively. Apart from the individual source study, we stacked the correlations of all sources and also those based on sub-samples. The time lag from the stacked correlation is +80 days for the whole sample and the distance travelled by the emission region corresponds to 7 pc. We also compared the start times of activity in radio and gamma rays of the correlated flares using Bayesian block representation. This shows that most of the flares at both wavebands start at almost the same time, implying a co-spatial origin of the activity. The correlated sources show more flares and are brighter in both bands than the uncorrelated ones.

15 pages, 8 figures and 4 tables. Published in MNRAS. Online-only Figure 6 is available as ancillary file with this submission

References in corpus (49)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database
• Planck 2013 results. I. Overview of products and scientific results
• Improved surrogate data for nonlinearity tests
• Fermi Large Area Telescope Second Source Catalog
• Leptonic and Hadronic Modeling of Fermi-Detected Blazars
• Limits and Confidence Intervals in the Presence of Nuisance Parameters
• Studies in Astronomical Time Series Analysis. VI. Bayesian Block Representations
• On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei
• Turbulent, Extreme Multi-Zone Model for Simulating Flux and Polarization Variability in Blazars
• Fast TeV variability in blazars: jets in a jet
• 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
• Doppler factors, Lorentz factors and viewing angles for quasars, BL Lacertae objects and radio galaxies
• Multi-Epoch VLBA Observations of EGRET-Detected Quasars and BL Lac Objects: Superluminal Motion of Gamma-Ray Bright Blazars
• A simple test for periodic signals in red noise
• Gamma-ray Light Curves and Variability of Bright Fermi-Detected Blazars
• Modeling the Emission Processes in Blazars
• Generating artificial light curves: Revisited and updated
• On the Reliability of Cross Correlation Function Lag Determinations in Active Galactic Nuclei
• Location of gamma-ray Flare Emission in the Jet of the BL Lacertae Object OJ287 more than 14pc from the Central Engine
• Constraining the location of the emitting region in Fermi blazars through rapid gamma-ray variability
• A Tight Connection between Gamma-Ray Outbursts and Parsec-Scale Jet Activity in the Quasar 3C 454.3
• Correlated Multi-Waveband Variability in the Blazar 3C~279 from 1996 to 2007
• Detection of significant cm to sub-mm band radio and gamma-ray correlated variability in Fermi bright blazars
• Synchrotron Self-Compton Model for Rapid Nonthermal Flares in Blazars with Frequency-Dependent Time Lags
• Rapid variability in TeV blazars: the case of PKS 2155-304
• Time-correlation between the radio and gamma-ray activity in blazars and the production site of the gamma-ray emission
• A method for the estimation of the significance of cross-correlations in unevenly sampled red-noise time series
• Transformation Properties of External Radiation Fields, Energy-Loss Rates and Scattered Spectra, and a Model for Blazar Variability
• The radio/gamma-ray connection in Active Galactic Nuclei in the era of the Fermi Large Area Telescope
• On the Location of the Gamma-ray Emission in the 2008 Outburst in the BL Lacertae Object AO 0235+164 through Observations across the Electromagnetic Spectrum
• Radio/gamma-ray time delay in the parsec-scale cores of active galactic nuclei
• Search for the shortest variability at gamma rays in flat-spectrum radio quasars
• Constraining the Location of Gamma-Ray Flares in Luminous Blazars
• Multiwavelength Variations of 3C 454.3 during the November 2010 to January 2011 Outburst
• Stochastic Modeling of the Fermi/LAT Gamma-ray Blazar Variability
• Relativistic Outflow Drives Gamma-Ray Emission in 3C345
• The connection between gamma-ray emission and millimeter flares in Fermi/LAT blazars
• Time dependent simulations of multiwavelength variability of the blazar Mrk 421 with a Monte Carlo multi-zone code
• Temporal Correlations Between Optical and Gamma-ray Activity in Blazars
• Catching the radio flare in CTA 102: II. VLBI kinematic analysis
• Improved AGN light curve analysis with the z-transformed discrete correlation function
• A structure and energy dissipation efficiency of relativistic reconfinement shocks
• Time series analysis of gamma-ray blazars and implications for the central black-hole mass
• Constraining the Physical Conditions in the Jets of Gamma-Ray Flaring Blazars using Centimeter-Band Polarimetry and Radiative Transfer Simulations. I. Data and Models for 0420-014, OJ 287, and 1156+295
• 3C273 variability at 7 mm: Evidences of shocks and precession in the jet
• Identification of gamma-ray emission from 3C345 and NRAO512

Cited by in corpus (37)

• Blazar flares powered by plasmoids in relativistic reconnection
• Long-term optical monitoring of TeV emitting Blazars
• RadioAstron Observations of the Quasar 3C273: a Challenge to the Brightness Temperature Limit
• Radio observations of active galactic nuclei with mm-VLBI
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. III. Characterisation of total flux density and polarisation variability of relativistic jets
• Multiwavelength Cross-Correlations and Flaring Activity in Bright Blazars
• A connection between $\gamma$-ray and parsec-scale radio flares in the blazar 3C 273
• Long-term study of Mkn 421 with the HAGAR Array of Telescopes
• Characteristic Variability Timescales in the Gamma-ray Power Spectra of Blazars
• A peculiar multi-wavelength flare in the Blazar 3C 454.3
• Discerning the $\gamma$-ray emitting region in the flat spectrum radio quasars
• The physical properties of $Fermi$-4LAC flat spectrum radio quasars
• Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and $\gamma$-ray activity in 2015$-$2016
• Exploring the nature of broadband variability in the FSRQ 3C 273
• Gamma-ray observations of low-luminosity active galactic nuclei
• Locating the gamma-ray emission site in Fermi/LAT blazars. II Multifrequency correlations
• What can the 2008/10 broadband flare of PKS 1502+106 tell us? Nuclear opacity, magnetic fields, and the location of gamma rays
• The Event Horizon Telescope Image of the Quasar NRAO 530
• H.E.S.S. detection of very-high-energy gamma-ray emission from the quasar PKS 0736+017
• Modelling blazar flaring using a time-dependent fluid jet emission model - an explanation for orphan flares and radio lags
• A multiband study and exploration of the radio wave - $\gamma$-ray connection in 3C 84
• Multi-wavelength observations of the gamma-ray flaring quasar S4 1030+61 in 2009-2014
• The long-term centimeter variability of active galactic nuclei: A new relation between variability timescale and accretion rate
• The Relativistic Jet Orientation and Host Galaxy of the Peculiar Blazar PKS 1413+135
• Multi-wavelength study of flaring activity in HBL 1ES 1959+650 during 2015-16
• Blazar Variability From Turbulence in Jets Launched by Magnetically Arrested Accretion Flows
• The first GeV flare of the radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447
• The flat-spectrum radio quasar 3C 345 from the high to the low emission state
• Multi-wavelength temporal variability of the blazar PKS 1510-089
• Investigating the connection between gamma-ray activity and relativistic jet in 3C273 during 2015-2019
• Multi-frequency Variability Study of Flat-Spectrum Radio Quasar PKS 0346-27
• PKS 1954-388: RadioAstron Detection on 80,000 km Baselines and Multiwavelength Observations
• A numerical study on the role of instabilities on multi-wavelength emission signatures of blazar jets
• Relationship between the $\gamma -$ray variability and the pc-scale jet in the blazar 3C 454.3
• Gamma-ray flares from the jet of the blazar CTA 102 in 2016-2018
• The core dominance parameter and \emph{Fermi} detection of extragalactic radio sources
• Modeling Fermi Large Area Telescope and Multiwavelength Data from Blazars