Discovery of very high energy gamma-ray emission from the blazar 1ES 1727+502 with the MAGIC Telescopes

TL;DR

This paper reports the first detection of very high energy gamma-ray emission from the blazar 1ES 1727+502 using MAGIC telescopes, confirming its VHE emission and modeling its spectral energy distribution.

Contribution

First-time detection of VHE gamma-ray emission from 1ES 1727+502 with detailed multiwavelength analysis and modeling.

Findings

VHE gamma-ray emission detected at 5.5 sigma significance.

Integral flux above 150 GeV is about 2.1% of Crab Nebula flux.

The VHE spectrum has a photon index of 2.7±0.5.

Abstract

Motivated by the Costamante & Ghisellini (2002) predictions we investigated if the blazar 1ES 1727+502 (z=0.055) is emitting very high energy (VHE, E>100 GeV) gamma rays. We observed the BL Lac object 1ES 1727+502 in stereoscopic mode with the two MAGIC telescopes during 14 nights between May 6th and June 10th 2011, for a total effective observing time of 12.6 hours. For the study of the multiwavelength spectral energy distribution (SED) we use simultaneous optical R-band data from the KVA telescope, archival UV/optical and X-ray observations by instruments UVOT and XRT on board of the Swift satellite and high energy (HE, 0.1 GeV - 100 GeV) gamma-ray data from the Fermi-LAT instrument. We detect, for the first time, VHE gamma-ray emission from 1ES 1727+502 at a statistical significance of 5.5 sigma. The integral flux above 150 GeV is estimated to be (2.1\pm0.4)% of the Crab Nebula flux and the de-absorbed VHE spectrum has a photon index of (2.7\pm0.5). No significant short-term variability was found in any of the wavebands presented here. We model the SED using a one-zone synchrotron self-Compton model obtaining parameters typical for this class of sources.