Time-resolved multiwavelength observations of the blazar VER J0521+211 from radio to gamma-ray 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 × 10 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.

Highlights from the VERITAS AGN Observation Program

“…This program proved immensely successful. During the 2013-14 season, five flaring blazars were detected by the snapshot program, including 1ES 0033+595 (∼20σ , ∼15% Crab), 1ES 1011+496 (peaking at ∼70% Crab), MS 1221.8+2452 (∼15% Crab), VER J0521+211 (peaking at ∼40% Crab; see [11]), and 1ES 1727+502 (∼10% Crab). These flares complemented other flares found via VERITAS' intense blazar monitoring programs (e.g.…”