Systematic Study of Gamma-ray bright Blazars with Optical Polarization and Gamma-ray Variability

Abstract

Blazars are highly variable active galactic nuclei which emit radiation at all wavelengths from radio to gamma-rays. Polarized radiation from blazars is one key piece of evidence for synchrotron radiation at low energies and it also varies dramatically. The polarization of blazars is of interest for understanding the origin, confinement, and propagation of jets. However, even though numerous measurements have been performed, the mechanisms behind jet creation, composition and variability are still debated. We performed simultaneous gamma-ray and optical photopolarimetry observations of 45 blazars between Jul. 2008 and Dec. 2014 to investigate the mechanisms of variability and search for a basic relation between the several subclasses of blazars. We identify a correlation between the maximum degree of optical linear polarization and the gamma-ray luminosity or the ratio of gamma-ray to optical fluxes. Since the maximum polarization degree depends on the condition of the magnetic field (chaotic or ordered), this result implies a systematic difference in the intrinsic alignment of magnetic fields in pc-scale relativistic jets between different types blazars (FSRQs vs. BL Lacs), and consequently between different types of radio galaxies (FR Is vs. FR IIs).

17 pages, 30 figures, 6 tables. Accepted for publication in Astrophysical Journal

References in corpus (5)

• Doppler factors, Lorentz factors and viewing angles for quasars, BL Lacertae objects and radio galaxies
• Unprecedented study of the broadband emission of Mrk 421 during flaring activity in March 2010
• RoboPol: The optical polarization of gamma-ray--loud and gamma-ray--quiet blazars
• Constraining the Location of Gamma-Ray Flares in Luminous Blazars
• The RINGO2 and DIPOL Optical Polarisation Catalogue of Blazars

Cited by in corpus (24)

• RoboPol: Connection between optical polarization plane rotations and gamma-ray flares in blazars
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. I. The program, calibration, and calibrators data products
• Jet precession driven by a supermassive black hole binary system in the BL Lac object PG 1553+113
• Blazars at the Cosmic Dawn
• A parsec-scale wobbling jet in the high-synchrotron peaked blazar PG 1553+113
• Multiwavelength variability power spectrum analysis of the blazars 3C 279 and PKS 1510-089 on multiple timescales
• Multi-band behaviour of the TeV blazar PG 1553+113 in optical range on diverse timescales
• Intra-night optical flux and polarization variability of BL~Lacertae during its 2020 $-$ 2021 high state
• Intra-Night Optical Variability Monitoring of Fermi Blazars: First Results from 1.3 m J C Bhattacharya Telescope
• Periodic Gamma-ray Modulation of the blazar PG 1553+113 Confirmed by Fermi-LAT and Multi-wavelength Observations
• Optical polarization variations in the blazar PKS 1749+096
• The RoboPol Program: Optical Polarimetric Monitoring of Blazars
• Study of correlation between optical flux and polarization variations in BL Lac objects
• Can Turbulence Dominate Depolarization of Optical Blazars?
• Origin of the UV to X-ray emission of radio galaxy NGC 1275 explored by analyzing its variability
• Chromatic optical polarization of BL Lac: while faint and bright
• Optical Spectropolarimetric Variability Properties in Blazars PKS 0637-75 and PKS 1510-089
• Short time-scale variability of $\gamma$-ray-emitting narrow-line Seyfert 1 galaxies in optical and UV bands
• Long-term optical and $\gamma -$ray variability of the blazar PKS~1222+216
• Follow-up Observations for IceCube-170922A: Detection of Rapid Near-Infrared Variability and Intensive Monitoring of TXS 0506+056
• Multiwavelength analysis of brightness variations of 3C~279: Probing the relativistic jet structure and its evolution
• The Method of Searching for Rotations of the Polarization Position Angle of Quasars
• Feature Selection for Classification of Blazars Based on Optical Photometric and Polarimetric Time-Series Data
• e-ASTROGAM mission: a major step forward for gamma-ray polarimetry