Multiwavelength Photometric and Spectropolarimetric Analysis of the FSRQ 3C 279

TL;DR

This study analyzes six years of multiwavelength data from 3C 279, revealing complex activity patterns, correlations across bands, and variability in gamma-ray emission mechanisms and locations.

Contribution

It provides a comprehensive multiwavelength analysis of 3C 279, identifying distinct activity periods and linking gamma-ray emission changes to the source's activity state.

Findings

Identified three activity periods with distinct behaviors.

Found correlations between UV, optical, and NIR emissions.

Observed variability and anti-correlation in gamma-ray spectral index.

Abstract

In this paper, we present light curves for 3C 279 over a time period of six years; from 2008 to 2014. Our multiwavelength data comprise 1 mm to gamma-rays, with additional optical polarimetry. Based on the behaviour of the gamma-ray light curve with respect to other bands, we identified three different activity periods. One of the activity periods shows anomalous behaviour with no gamma-ray counterpart associated with optical and NIR flares. Another anomalous activity period shows a flare in gamma-rays, 1 mm and polarization degree, however, it does not have counterparts in the UV continuum, optical and NIR bands. We find a significant overall correlation of the UV continuum emission, the optical and NIR bands. This correlation suggests that the NIR to UV continuum is co-spatial. We also find a correlation between the UV continuum and the 1 mm data, which implies that the dominant process in producing the UV continuum is synchrotron emission. The gamma-ray spectral index shows statistically significant variability and an anti-correlation with the gamma-ray luminosity. We demonstrate that the dominant gamma-ray emission mechanism in 3C 279 changes over time. Alternatively, the location of the gamma-ray emission zone itself may change depending on the activity state of the central engine.