Discovery of VHE gamma-rays from Centaurus A

TL;DR

This paper reports the first detection of very high energy gamma-ray emission from the radio galaxy Centaurus A, confirming it as a source of TeV particles and expanding the class of known VHE emitters.

Contribution

It presents the discovery of VHE gamma-ray emission from Centaurus A using H.E.S.S., establishing radio galaxies as a new class of VHE gamma-ray sources.

Findings

Significant detection of VHE gamma-rays from Centaurus A

Measured flux is 0.8% of Crab Nebula flux

Spectrum follows a power law with index 2.7

Abstract

We report the discovery of faint very high energy (VHE, E > 100 GeV) gamma-ray emission from the radio galaxy Centaurus A in deep observations performed with the H.E.S.S. experiment. A signal with a statistical significance of 5.0 sigma is detected from the region including the radio core and the inner kpc jets. The integral flux above an energy threshold of ~250 GeV is measured to be 0.8% of the flux of the Crab Nebula and the spectrum can be described by a power law with a photon index of 2.7 +/- 0.5_stat +/- 0.2_sys. No significant flux variability is detected in the data set. The discovery of VHE gamma-ray emission from Centaurus A reveals particle acceleration in the source to >TeV energies and, together with M 87, establishes radio galaxies as a class of VHE emitters.