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Very high energy gamma ray emission from the active galactic nucleus PG1553+113 was observed during 2005 and 2006 by the MAGIC collaboration, for atotal observation time of 18.8 hours. Here we present the results of follow upobservations: more than 20 hours of good quality data collected by the MAGICTelescope during the 2007 and 2008 campaigns. The obtained spectra are comparedand combined with previous measurements, and corrected for absorption adoptingdifferent EBL models. Upper limits on the unknown source redshift are derivedby assuming the absence of a break in the intrinsic spectrum, or alternativelyby constraining the hardness of the intrinsic source spectrum.

A new upper limit on the redshift of PG 1553+113 from observations with the MAGIC Telescope