The MAGIC telescope has observed very high energy gamma-ray emission from the BL Lac object PG 1553+113 in 2005 and 2006 at an overall significance is 8.8 sigma in 18.8h. The light curve shows no significant flux variations on a daily time-scale. The flux level during 2005 was, however, significantly higher compared to 2006. The differential energy spectrum between ~90 GeV and 500 GeV is well described by a power law with a spectral index of -4.2+-0.3. The inferred photon energy spectrum allows to pose an upper limit on the (yet undetermined) redshift of the PG 1553+113.

MAGIC 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 889-892