Spectral variability of the blazar 3C 279 in the optical to X-ray band during 2009-2018

Abstract

We report on spectral variability of the blazar 3C 279 in the optical to X-ray band between MJD 55100 and 58400 during which long-term radio variability was observed. We construct light curves and band spectra in each of the optical ($2\times 10^{14}$-$1.5\times 10^{15}$ Hz) and X-ray (0.3-10 keV) bands, measure the spectral parameters (flux $F$ and spectral index $\alpha$), and investigate correlation between $F$ and $\alpha$ within and across the bands. We find that the correlation of the optical properties dramatically change after $\sim$MJD 55500 and the light curves show more frequent activity after $\sim$MJD 57700. We therefore divide the time interval into three "states" based on the correlation properties and source activity in the light curves, and analyze each of the three states separately. We find various correlations between the spectral parameters in the states and an intriguing 65-day delay of the optical emission with respect to the X-ray one in state 2 (MJD 55500-57700). We attempt to explain these findings using a one-zone synchro-Compton emission scenario.

11 pages, 4 figures; Accepted for publication in ApJ

References in corpus (11)

• A change in the optical polarization associated with a gamma-ray flare in the blazar 3C 279
• Rapid Variability of Blazar 3C 279 during Flaring States in 2013-2014 with Joint Fermi-LAT, NuSTAR, Swift, and Ground-Based Multi-wavelength Observations
• Correlated Multi-Waveband Variability in the Blazar 3C~279 from 1996 to 2007
• Multi-wavelength observations of 3C 279 during the extremely bright gamma-ray flare in 2014 March-April
• Long-term radio variability of AGN: flare characteristics
• Through The Ring Of Fire: $\gamma$-Ray Variability In Blazars By A Moving Plasmoid Passing A Local Source Of Seed Photons
• Multiwavelength behaviour of the blazar 3C279: decade-long study from $\gamma$-ray to radio
• Seed Photon Fields of Blazars in the Internal Shock Scenario
• 3C 279 in Outburst in June 2015: A Broadband-SED Study Based on the INTEGRAL Detection
• Broadband variability and correlation study of 3C 279 during flare of 2017-2018
• Multiwavelength analysis of brightness variations of 3C~279: Probing the relativistic jet structure and its evolution

Cited by in corpus (3)

• The Changing Look Blazar B2 1420+32
• Variability and Spectral Characteristics of Three Flaring Gamma-ray Quasars Observed by VERITAS and Fermi-LAT
• Understanding the Broadband Emission Process of 3C 279 through Longterm Spectral Analysis