Gabriele Cologna LSW Heidelberg

VHE emission from AGN and constrains on the Extragalactic Magnetic Field - The case of 1ES 0229+200. (pdf)

The high-frequency peaked BL Lac Object (HBL) 1ES 0229+200 is a well known Active Galactic Nucleus (AGN) with a redshift of ~0.14. It was first detected in Very High Energy (VHE, E>100 GeV) gamma rays by H.E.S.S. (High Energy Stereoscopic System) in 2006 [Aharonian et al.(2007)]. Due to its relative high distance (for the VHE range) and its spectral characterics (hard spectrum and constant flux), it has been used to derive constraints on the Extragalactic Background Light (EBL) [Aharonian et al.(2007)] and on the Intergalactic Magnetic Field (IGMF) [Tavecchio et al.(2010), Dermer et al.(2011)]. New observations at VHE (Benbow 2011) and X-rays (Kaufmann, in preparation) show however signs of monthly flux variability. This will affect the derivation of the constraints on both EBL and IGMF. Aharonian, F. et al., (HESS Coll.), A&A, 2007, 475, L9 Tavecchio, F. et al., MNRAS, 2010, 406, L70 Dermer, C.D. et al., ApJ, 2011, 733, L21 Benbow, W. for the VERITAS Coll., in 32ND ICRC, 2011