Multiwavelength analysis and the C IV {\lambda}1549 {\AA} emission line behavior from 2008 to 2020 of the FSRQ B2 1633+382

TL;DR

This study analyzes multiwavelength data from 2008 to 2020 of the FSRQ B2 1633+382, revealing correlations between emission lines and continuum, estimating the gamma-ray emission region distance, and proposing models for jet and BLR interactions.

Contribution

It provides a detailed multiwavelength analysis of B2 1633+382, including emission line behavior, delay measurements, and insights into the BLR and gamma-ray production mechanisms.

Findings

Correlation between line and continuum emission with near-zero delay

Estimated gamma-ray emission region at ~37 pc from jet apex

Evidence of BLR outflow and magnetic reconnection in gamma-ray flares

Abstract

The flat-spectrum radio quasar B2 1633+382 (4C 38.41) has been monitored for several years and has presented correlated variability in multiple wavelengths. In this article, we are performing different analyses for multiple frequencies, from gamma-rays to radio, as well as, the C IV ${\lambda}$1549 {\AA} emission line and the ${\lambda}$1350 {\AA} continuum. Using the non-thermal dominance parameter, we separated the C IV and the continuum light curves for when the dominant source of continuum is the accretion disk or the jet. We found a correlation at a delay consistent with zero between the line and the continuum dominated by disk emission indicating a very small broad-line region (BLR). From the resulting delay between the 15 GHz and gamma-rays, we estimated the distance of the gamma-ray emission region from the jet apex to be $\sim$37 pc. The C IV flux decreases when the continuum and gamma-rays increase at some of the high activity periods. The C IV profile presents a larger variable component in its blue wing. The relation between the luminosities of C IV and the continuum does not completely follow the relation for a quasar sample. Our results lead us to propose an outflow of BLR material in the jet-flow direction, a gamma-ray production through magnetic reconnection for the flaring event of mid-2011, and that there is not enough BLR material close to the radio core to be easily ionized by the non-thermal continuum.