The extreme synchrotron BL Lac object PKS 0548-322 has been observed with the High Energy Stereoscopic System (H.E.S.S) array of atmospheric-Cherenkov telescopes. The observations were performed between October 2004 and December 2006 for a total exposure of nearly 25 hours live-time. We will report the HESS detection and present a spectral energy distribution of this object using a quasi-simultaneous X-ray spectrum from archival data. It will be used to estimate some general constraints on source parameters.

for the H.E.S.S collaboration

Proceedings of the 30th International Cosmic Ray Conference; Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.); Universidad Nacional Autónoma de México, Mexico City, Mexico, 2008; Vol. 3 (OG part 2), pages 913-916