Multiwavelength Analysis and the C iv λ1549 Å Emission Line Behavior From 2008 to 2020 of FSRQ B2 1633+382

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 angstrom emission line and the lambda 1350 angstrom continuum. Using the nonthermal 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 similar to 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 nonthermal continuum.

Automated summary

The flat-spectrum radio quasar B2 1633+382 has been studied at multiple frequencies, showing correlated variability in the C iv emission line and continuum light curves. The delay between the line and continuum suggests a small broad-line region (BLR), and the distance of the gamma-ray emission region from the jet apex is estimated to be 37 pc.