Time-resolved multiwavelength observations of the blazar VER J0521+211 from radio to gamma-ray energies

TL;DR

This paper presents a detailed multiwavelength observational study of the blazar VER J0521+211, revealing flux variability across the spectrum and discussing emission mechanisms over a two-year campaign.

Contribution

It provides the first comprehensive multiwavelength dataset for VER J0521+211, including spectral and variability analysis from radio to gamma-ray energies.

Findings

Detected significant flux variability at all wavelengths.

Observed a long-lasting high gamma-ray state in Fall 2013.

Presented nightly-resolved spectra at X-ray and TeV energies.

Abstract

VER J0521+211 (RGB J0521.8+2112) is one of the brightest and most powerful blazars detected in the TeV gamma-ray regime. It is located at a redshift of z=0.108 and since its discovery in 2009, VER J0521+211 has exhibited an average TeV flux exceeding 0.1 times that of the Crab Nebula, corresponding to an isotropic luminosity of $3\times10^{44}$ erg s$^{-1}$. We present data from a comprehensive multiwavelength campaign on this object extending between November 2012 and February 2014, including single-dish radio observations, optical photometry and polarimetry, UV, X-ray, GeV and TeV gamma-ray data (VERITAS, MAGIC). Significant flux variability was observed at all wavelengths, including a long-lasting high state at gamma-ray energies in Fall 2013. Nightly-resolved spectra at X-ray and TeV energies are be presented, and emission mechanisms explaining the observed flux and spectral variability are discussed.