The magnetic field structure in CTA 102 from high resolution mm-VLBI observations during the flaring state in 2016-2017

Abstract

Investigating the magnetic field structure in the innermost regions of relativistic jets is fundamental to shed light on the crucial physical processes giving rise to the jet formation, as well as to its extraordinary radiation output up to gamma-ray energies. We study the magnetic field structure of the quasar CTA 102 with 3 and 7 mm-VLBI polarimetric observations, reaching an unprecedented resolution (~50 microarcsec). We also investigate the variability and physical process occurring in the source during the observing period which coincides with a very active state of the source till high-energies. The Faraday rotation analysis between 3 and 7mm shows a gradient in rotation measure with a maximum value of ~6X10^4 rad/m^2 and intrinsic electric vector position angles (EVPAs) oriented around the centroid of the core, suggesting the presence of large-scale helical magnetic fields. Such a magnetic field structure is also visible in 7 mm images when a new superluminal component is crossing the core region. The 7mm EVPAs orientation is different when the component is exiting the core or crossing a stationary feature at ~0.1 mas. The interaction between the superluminal component and a recollimation shock at ~0.1 mas could have triggered the multi-wavelengths flares. The variability Doppler factor associated with such interaction is large enough to explain the high energy emission, as we infer from the analysis of gamma-ray and X-ray data, and it is in agreement with the Doppler factor obtained to explain the extraordinary optical flare by Raiteri et al.(2017).

arXiv commentPublished in Astronomy & Astrophysics

References in corpus (28)

• Planck 2015 results. XIII. Cosmological parameters
• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• Fermi Large Area Telescope Second Source Catalog
• Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Jet Kinematics from Bimonthly Monitoring with the Very Long Baseline Array
• Probing the Inner Jet of the Quasar PKS 1510-089 with Multi-waveband Monitoring during Strong Gamma-ray Activity
• Kinematics of Parsec-Scale Jets of Gamma-Ray Blazars at 43~GHz within the VLBA-BU-BLAZAR Program
• MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. VIII. Faraday rotation in parsec-scale AGN jets
• MOJAVE - XIV. Shapes and opening angles of AGN jets
• Blazar spectral variability as explained by a twisting inhomogeneous jet
• Multiwaveband Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Correlated Polarization Behavior
• Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron. I. Imaging BL Lacertae at 21 microarcsecond resolution
• RoboPol: First season rotations of optical polarization plane in blazars
• Synchrotron radiation of self-collimating relativistic MHD jets
• Catching the Radio Flare in CTA 102 III. Core-Shift and Spectral Analysis
• Parsec-scale Faraday Rotation Measures from General Relativistic MHD Simulations of Active Galactic Nuclei Jets
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. I. The program, calibration, and calibrators data products
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. III. Characterisation of total flux density and polarisation variability of relativistic jets
• A multi-wavelength polarimetric study of the blazar CTA 102 during a Gamma-ray flare in 2012
• Catching the radio flare in CTA 102: II. VLBI kinematic analysis
• On the Calibration of Full-polarization 86GHz Global VLBI Observations
• Comprehensive Monitoring of Gamma-ray Bright Blazars. I. Statistical Study of Optical, X-ray, and Gamma-ray Spectral Slopes
• On the multi-wavelength Emission from CTA 102
• Polarization swings in blazars
• Very Long Baseline polarimetry and the gamma-ray connection in Markarian 421 during the broadband campaign in 2011
• Fermi-Large Area Telescope observations of the brightest Gamma-ray flare ever detected from CTA 102
• Revealing the Nature of Blazar Radio Cores through Multi-Frequency Polarization Observations with the Korean VLBI Network
• On the location of the supermassive black hole in CTA 102
• CTA 102 in exceptionally high state during 2016-17

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• Investigating the multiwavelength behaviour of the flat spectrum radio quasar CTA 102 during 2013-2017
• The jet collimation profile at high resolution in BL Lacertae
• Enabling Transformational ngEHT Science via the Inclusion of 86 GHz Capabilities
• New jet feature in the parsec-scale jet of the blazar OJ287 connected to the 2017 teraelectronvolt flaring activity
• Modeling the time variable spectral energy distribution of the blazar CTA 102 from 2008 to 2022
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• Jet Collimation and Acceleration in the Flat Spectrum Radio Quasar 1928+738
• Radio VLBA polarization and multi-band monitoring of the high-redshift quasar S5 0836+710 during a high activity period
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• Constraints on VHE gamma-ray emission of Flat Spectrum Radio Quasars with the MAGIC telescopes
• Kilogauss magnetic field and jet dynamics in the quasar NRAO 530
• Gamma-ray flares from the jet of the blazar CTA 102 in 2016-2018
• Multifrequency simultaneous VLBA view of the radio source 3C 111
• Waiting times between gamma-ray flares of Flat Spectrum Radio Quasars, and constraints on emission processes
• Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron. V. Space and ground millimeter-VLBI imaging of OJ 287