Synchrotron emission from the blazar PG 1553+113. An analysis of its flux and polarization variability

Abstract

In 2015 July 29 - September 1 the satellite XMM-Newton pointed at the BL Lac object PG 1553+133 six times, collecting data for 218 hours. During one of these epochs, simultaneous observations by the Swift satellite were requested to compare the results of the X-ray and optical-UV instruments. Optical, near-infrared and radio monitoring was carried out by the Whole Earth Blazar Telescope (WEBT) collaboration for the whole observing season. We here present the results of the analysis of all these data, together with an investigation of the source photometric and polarimetric behaviour over the last three years. The 2015 EPIC spectra show slight curvature and the corresponding light curves display fast X-ray variability with a time scale of the order of 1 hour. In contrast to previous results, during the brightest X-ray states detected in 2015 the simple log-parabolic model that best-fits the XMM-Newton data also reproduces reasonably well the whole synchrotron bump, suggesting a peak in the near-UV band. We found evidence of a wide rotation of the polarization angle in 2014, when the polarization degree was variable, but the flux remained almost constant. This is difficult to interpret with deterministic jet emission models, while it can be easily reproduced by assuming some turbulence of the magnetic field.

arXiv comment15 pages, 12 figures, accepted by Monthly Notices of the Royal Astronomical Society

References in corpus (40)

• On the Absorption of X-rays in the Interstellar Medium
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• The Swift X-ray Telescope
• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• The Swift Ultra-Violet/Optical Telescope
• The XMM-Newton Optical/UV Monitor Telescope
• Turbulent, Extreme Multi-Zone Model for Simulating Flux and Polarization Variability in Blazars
• Probing the Inner Jet of the Quasar PKS 1510-089 with Multi-waveband Monitoring during Strong Gamma-ray Activity
• Log-parabolic spectra and particle acceleration in the BL Lac object Mkn 421: spectral analysis of the complete BeppoSAX wide band X-ray data set
• Multiwavelength Evidence for Quasi-periodic Modulation in the Gamma-ray Blazar PG 1553+113
• Relativistic beaming and gamma-ray brightness of blazars
• HST/COS Observations of the Ly alpha Forest toward the BL Lac Object 1ES1553+113
• Extreme blazars as counterparts of IceCube astrophysical neutrinos
• Results of WEBT, VLBA and RXTE monitoring of 3C 279 during 2006-2007
• The awakening of BL Lacertae: observations by Fermi, Swift, and the GASP-WEBT
• Setting UBVRI Photometric Zero-Points Using Sloan Digital Sky Survey ugriz Magnitudes
• SBS 0846+513: a new gamma-ray emitting Narrow-Line Seyfert 1 galaxy
• The Outburst of the Blazar S5 0716+71 in 2011 October: Shock in a Helical Jet
• RoboPol: The optical polarization of gamma-ray--loud and gamma-ray--quiet blazars
• RoboPol: First season rotations of optical polarization plane in blazars
• MAGIC gamma-ray and multifrequency observations of flat spectrum radio quasar PKS 1510-089 in early 2012
• Synchrotron Polarization in Blazars
• The 2012 flare of PG 1553+113 seen with H.E.S.S. and Fermi-LAT
• Variability of the blazar 4C 38.41 (B3 1633+382) from GHz frequencies to GeV energies
• RoboPol: Do optical polarization rotations occur in all blazars?
• Rapid Multiwaveband Polarization Variability in the Quasar PKS 0420-014: Optical Emission from the Compact Radio Jet
• Exceptional outburst of the blazar CTA 102 in 2012: The GASP-WEBT campaign and its extension
• PG 1553+113: five years of observations with MAGIC
• Fermi Observations of the Very Hard Gamma-ray Blazar PG 1553+113
• The WEBT campaign on the BL Lac object PG 1553+113 in 2013. An analysis of the enigmatic synchrotron emission
• Photometrically Triggered Keck Spectroscopy of Fermi BL Lac Objects
• Polarization Signatures of Relativistic Magnetohydrodynamic Shocks in the Blazar Emission Region - I. Force-free Helical Magnetic Fields
• Multiwavelength behaviour of the blazar OJ 248 from radio to γ-rays
• Chandra View of the Warm-Hot IGM toward 1ES 1553+113: Absorption Line Detections and Identifications (Paper I)
• Spectroscopy of BL Lac objects of extraordinary luminosity
• Infrared properties of blazars: putting the GASP-WEBT sources into context
• Probing the very-high-energy gamma-ray spectral curvature in the blazar PG 1553+113 with the MAGIC telescopes
• Polarization swings from curved trajectories of the emitting regions
• Multi-Wavelength Photometric and Polarimetric Observations of the Outburst of 3C 454.3 in Dec. 2009
• Analyzing polarization swings in 3C 279

Cited by in corpus (18)

• Probing Blazar Emission Processes with Optical/Gamma-ray Flare Correlations
• RoboPol: A four-channel optical imaging polarimeter
• Jet precession driven by a supermassive black hole binary system in the BL Lac object PG 1553+113
• Dissecting the long-term emission behaviour of the BL Lac object Mrk 421
• The complex variability of blazars: Time-scales and periodicity analysis in S4 0954+65
• A parsec-scale wobbling jet in the high-synchrotron peaked blazar PG 1553+113
• Optical Flux and Spectral Variability of the TeV blazar PG 1553+113
• The optical behaviour of BL Lacertae at its maximum brightness levels: a blend of geometry and energetics
• Multi-band Variability of the TeV Blazar PG 1553+113 with XMM-Newton
• Constraining the PG 1553+113 binary hypothesis: interpreting hints of a new, 22-year period
• Polarimetric Properties of Blazars Caught by the WEBT
• A flat-spectrum flare in S4 0444+63 revealed by a new implementation of multi-wavelength single-dish observations
• The beamed jet and quasar core of the distant blazar 4C 71.07
• The variability patterns of the TeV blazar PG 1553+113 from a decade of MAGIC and multi-band observations
• New Tests of Millilensing in the Blazar PKS 1413+135
• Testing particle acceleration in blazar jets with continuous high-cadence optical polarization observations
• X-Ray Spectral Variability of the TeV HBL Blazar PG 1553+113 with XMM-Newton
• Constraints on magnetic field and particle content in blazar jets through optical circular polarization