Upper Limits from HESS Observations of AGN in 2005-2007

TL;DR

This paper reports on HESS observations of AGN from 2005-2007, providing upper limits for VHE gamma-ray emission from twelve candidate sources and results from four known VHE-bright AGN, with some simultaneous X-ray data.

Contribution

It presents the first set of integral flux upper limits for selected AGN candidates and reports observational results for known VHE-bright AGN during 2005-2007.

Findings

Upper limits established for 12 candidate AGN.

No significant VHE detection for 4 known AGN.

Simultaneous X-ray data for three AGN.

Abstract

Very high energy (VHE; >100 GeV) observations of a sample of selected active galactic nuclei (AGN) were performed between January 2005 and April 2007 with the High Energy Stereoscopic System (HESS), an array of imaging atmospheric-Cherenkov telescopes. Significant detections are reported elsewhere for many of these objects. Here, integral flux upper limits for twelve candidate very high energy (VHE; >100 GeV) gamma-ray emitters are presented. In addition, results from HESS observations of four known VHE-bright AGN are given although no significant signal is measured. For three of these AGN (1ES 1101-232, 1ES 1218+304, and Mkn 501) simultaneous data were taken with the Suzaku X-ray satellite.