PKS 1502+106: A high-redshift Fermi blazar at extreme angular resolution. Structural dynamics with VLBI imaging up to 86 GHz

Abstract

Context. Blazars are among the most energetic objects in the Universe. In 2008 August, Fermi/LAT detected the blazar PKS 1502+106 showing a rapid and strong gamma-ray outburst followed by high and variable flux over the next months. This activity at high energies triggered an intensive multi-wavelength campaign covering also the radio, optical, UV, and X-ray bands indicating that the flare was accompanied by a simultaneous outburst at optical/UV/X-rays and a delayed outburst at radio bands. Aims: In the current work we explore the phenomenology and physical conditions within the ultra-relativistic jet of the gamma-ray blazar PKS 1502+106. Additionally, we address the question of the spatial localization of the MeV/GeV-emitting region of the source. Methods: We utilize ultra-high angular resolution mm-VLBI observations at 43 and 86 GHz complemented by VLBI observations at 15 GHz. We also employ single-dish radio data from the F-GAMMA program at frequencies matching the VLBI monitoring. Results: PKS 1502+106 shows a compact core-jet morphology and fast superluminal motion with apparent speeds in the range 5--22 c. Estimation of Doppler factors along the jet yield values between ~7 up to ~50. This Doppler factor gradient implies an accelerating jet. The viewing angle towards the source differs between the inner and outer jet, with the former at ~3 degrees and the latter at ~1 degree, after the jet bends towards the observer beyond 1 mas. The de-projected opening angle of the ultra-fast, magnetically-dominated jet is found to be (3.8 +/- 0.5) degrees. A single jet component can be associated with the pronounced flare both at high-energies and in radio bands. Finally, the gamma-ray emission region is localized at less than 5.9 pc away from the jet base.

22 pages, 12 figures. Accepted for publication in A&A

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Cited by in corpus (25)

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• Cosmic neutrinos from temporarily gamma-suppressed blazars
• A ring accelerator? Unusual jet dynamics in the IceCube candidate PKS 1502+106
• Inner jet kinematics and the viewing angle towards the γ-ray narrow-line Seyfert 1 galaxy 1H 0323+342
• What can the 2008/10 broadband flare of PKS 1502+106 tell us? Nuclear opacity, magnetic fields, and the location of gamma rays
• Exploring the origin of multiwavelength activities of high-redshift FSRQ PKS 1502+106 during 2014-2018
• A multiband study and exploration of the radio wave - $\gamma$-ray connection in 3C 84
• Curvature induced polarization and spectral index behavior for PKS 1502+106
• Multi-wavelength observations of the gamma-ray flaring quasar S4 1030+61 in 2009-2014
• Jet kinematics in the transversely stratified jet of 3C 84 A two-decade overview
• FERMI transient J1544-0649: a flaring radio-weak BL Lac
• Localizing the $\gamma$-ray emitting region in the blazar TXS 2013+370
• Diversity of gamma-ray and Radio Variabilities of Bright Blazars and Implications for gamma-ray Emission Location
• Repeated pattern of $\gamma$-ray flares in the blazar PKS 1502+106 coincident with the IC190730A neutrino event
• Searching for temporary gamma-ray dark blazars associated with IceCube neutrinos
• European VLBI Network Observations of the Proposed Dual AGN SDSS J101022.95+141300.9
• Neutrino production in blazar radio cores
• Sub-milliarcsecond imaging of a bright flare and ejection event in the extragalactic jet 3C 111
• The Observation of High-Energy Neutrinos from the Cosmos: Lessons Learned for Multimessenger Astronomy
• Very Long Baseline Interferometry Observations of the Proposed Radio Counterpart of an EGRET Source
• Multi-messenger emission from the parsec-scale jet of the flat-spectrum radio quasar PKS 1502+106 coincident with high-energy neutrino IceCube-190730A
• Selected results from IceCube