2017/08/02 by M. Cerruti, Cerruti, Matteo, J.-P. Lenain +3
Engineering · Physics and Astronomy · #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Neutrino Physics Research #Particle Accelerators and Free-Electron Lasers
paper · doi:10.48550/arxiv.1708.00658
openalex publication_date 2017/08/02 · openalex created_date 2022/09/03 · openalex updated_date 2026/07/28
With the installation of a new 28-m diameter imaging atmospheric Cherenkov telescope in the middle of the array, the H.E.S.S. instrument has entered since 2012 into its Phase II. The fifth large-size telescope is particularly important to lower the threshold energy of the array, and is thus a unique instrument to observe low-frequency-peaked blazars, such as flat-spectrum radio-quasars (FSRQs), which remain rare in the very-high- energy (VHE; E > 100 GeV) γ-ray domain. In this contribution, we report on the discovery with the H.E.S.S. telescopes of VHE γ-ray emission from the FSRQ PKS 0736+017 (z=0.189). H.E.S.S. observations were triggered as a target-of-opportunity in February 2015 following the detection of γ-ray flaring activity in the MeV-GeV energy-band with Fermi-LAT. Significant VHE emission is detected with H.E.S.S. only during one of the nights of the observing campaign, showing at least night-by-night variability in the VHE regime. We discuss the location of the γ-ray emitting region within the relativistic jet, using opacity and variability constraints.