Multi-wavelength observations of the gamma-ray flaring quasar S4 1030+61 in 2009-2014

TL;DR

This study analyzes five years of multi-wavelength observations of quasar S4 1030+61, revealing jet dynamics, polarization changes, and the spatial relationship between radio and gamma-ray emission regions, enhancing understanding of quasar jet physics.

Contribution

It provides the first detailed multi-frequency, multi-epoch analysis of S4 1030+61, linking radio and gamma-ray emission regions and characterizing jet properties during active periods.

Findings

Jet exhibits superluminal motion of 6.4c

Gamma-ray emission is located within 1 parsec of the core

Radio flares correlate with particle injection and energy losses

Abstract

We present a study of the parsec-scale multi-frequency properties of the quasar S4 1030+61 during a prolonged radio and gamma-ray activity. Observations were performed within Fermi gamma-ray telescope, OVRO 40-m telescope and MOJAVE VLBA monitoring programs, covering five years from 2009. The data are supplemented by four-epoch VLBA observations at 5, 8, 15, 24, and 43 GHz, which were triggered by the bright gamma-ray flare, registered in the quasar in 2010. The S4 1030+61 jet exhibits an apparent superluminal velocity of (6.4+-0.4)c and does not show ejections of new components in the observed period, while decomposition of the radio light curve reveals nine prominent flares. The measured variability parameters of the source show values typical for Fermi-detected quasars. Combined analysis of radio and gamma-ray emission implies a spatial separation between emitting regions at these bands of about 12 pc and locates the gamma-ray emission within a parsec from the central engine. We detected changes in the value and direction of the linear polarization and the Faraday rotation measure. The value of the intrinsic brightness temperature of the core is above the equipartition state, while its value as a function of distance from the core is well approximated by the power-law. Altogether these results show that the radio flaring activity of the quasar is accompanied by injection of relativistic particles and energy losses at the jet base, while S4 1030+61 has a stable, straight jet well described by standard conical jet theories.