Discovery of VHE gamma-ray emission from the BL Lac object B3 2247+381 with the MAGIC telescopes

TL;DR

This paper reports the first detection of VHE gamma-ray emission from the BL Lac object B3 2247+381, using MAGIC telescopes, complemented by multiwavelength observations, and models its spectral energy distribution with a one-zone SSC model.

Contribution

First detection of VHE gamma-ray emission from B3 2247+381 with detailed multiwavelength data and spectral modeling.

Findings

Detected VHE gamma-ray emission at 5.6 sigma significance.

Measured a soft VHE spectrum with photon index -3.2.

Spectral energy distribution modeled successfully with a one-zone SSC model.

Abstract

We study the non-thermal jet emission of the BL Lac object B3 2247+381 during a high optical state. The MAGIC telescopes observed the source during 13 nights between September 30th and October 30th 2010, collecting a total of 14.2 hours of good quality very high energy (VHE) $\gamma$-ray data. Simultaneous multiwavelength data was obtained with X-ray observations by the Swift satellite and optical R-band observations at the KVA-telescope. We also use high energy $\gamma$-ray (HE, 0.1 GeV-100 GeV) data from the Fermi satellite. The BL Lac object B3 2247+381 (z=0.119) was detected, for the first time, at VHE $\gamma$-rays at a statistical significance of 5.6 $\sigma$. A soft VHE spectrum with a photon index of -3.2 $\pm$ 0.6 was determined. No significant short term flux variations were found. We model the spectral energy distribution using a one-zone SSC-model, which can successfully describe our data.