H.E.S.S and Fermi-LAT discovery of gamma rays from the blazar 1ES 1312-423

TL;DR

This paper reports the discovery of gamma-ray emissions from the faint blazar 1ES 1312-423 using H.E.S.S. and Fermi-LAT, covering a broad energy spectrum and modeled with synchrotron self-Compton and black-body components.

Contribution

First detection of gamma rays from 1ES 1312-423 at very high energies and high energies, with detailed spectral energy distribution analysis.

Findings

Gamma-ray flux at 1 TeV is 0.5% of Crab flux.

Detected a hard spectrum at high energies with index 1.4.

Spectral energy distribution fitted with SSC and black-body models.

Abstract

A deep observation campaign carried out by the High Energy Stereoscopic System (H.E.S.S.) on Centaurus A enabled the discovery of gamma rays from the blazar 1ES 1312-423, two degrees away from the radio galaxy. With a differential flux at 1 TeV of (1.9 +/-0.6(stat) +/-0.4(sys)) x 10^{-13} /cm^2 /s /TeV corresponding to 0.5% of the Crab nebula differential flux and a spectral index of 2.9 +/- 0.5 (stat) +/- 0.2 (sys), 1ES 1312-423 is one of the faintest sources ever detected in the very high energy (E>100 GeV) extragalactic sky. A careful analysis using three and a half years of Fermi-LAT data allows the discovery at high energies (E>100 MeV) of a hard spectrum (index of 1.4 +/- 0.4 (stat) +/- 0.2 (sys)) source coincident with 1ES 1312-423. Radio, optical, UV and X-ray observations complete the spectral energy distribution of this blazar, now covering 16 decades in energy. The emission is successfully fitted with a synchrotron self Compton model for the non-thermal component, combined with a black-body spectrum for the optical emission from the host galaxy.