Target of Opportunity observations of blazars with H.E.S.S. 

Abstract

The very high energy (VHE, E > 100 GeV) sky is dominated by blazars, radio-loud active galactic nuclei whose relativistic jet is closely aligned with the line of sight. Blazars are characterized by rapid variability at all wavelengths and thus an important part of the H.E.S.S. blazar program is devoted to target of opportunity (ToO) observations. H.E.S.S. triggers blazar ToOs on the basis of publicly available blazar observations at longer wavelengths (optical, X-rays, and $\gamma$-rays), from private optical observations with the ATOM telescope, and from private communications by $\gamma$-ray partners in the context of MoUs. In 2015, about 70 hours of H.E.S.S. data were taken in the form of blazar ToOs, which represents ~15$\%$ of all extragalactic observations. In this contribution, we present the H.E.S.S. blazar ToO status, and we focus on two major results from the 2015 season: the detection of VHE emission from 3C 279 during the June 2015 flare, and the discovery of PKS 0736+017 as a new VHE quasar.

arXiv comment6 pages, 4 figures. To appear in the proceedings of the 6th International Symposium on High-Energy Gamma-Ray Astronomy (Gamma2016), Heidelberg, Germany, July 11-15, 2016

References in corpus (9)

• Very-High-Energy Gamma Rays from a Distant Quasar: How Transparent Is the Universe?
• MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21
• A high performance likelihood reconstruction of gamma-rays for Imaging Atmospheric Cherenkov Telescopes
• Minute-Timescale >100 MeV gamma-ray variability during the giant outburst of quasar 3C 279 observed by Fermi-LAT in 2015 June
• A Monte Carlo Template based analysis for Air-Cherenkov Arrays
• Very-high-energy gamma-rays from the Universe's middle age: detection of the z=0.940 blazar PKS 1441+25 with MAGIC
• Gamma rays from the quasar PKS 1441+25: story of an escape
• Magellan Spectroscopy of Low-Redshift Active Galactic Nuclei
• Upper limits from five years of blazar observations with the VERITAS Cherenkov telescopes

Cited by in corpus (1)

• Constraints on the emission region of 3C 279 during strong flares in 2014 and 2015 through VHE gamma-ray observations with H.E.S.S