  Very high energy (VHE; >100 GeV) gamma-ray observations of PG 1553+113 were
made with the High Energy Stereoscopic System (HESS) in 2005 and 2006. A strong
signal, ~10 standard deviations, is detected by HESS during the 2 years of
observations (24.8 hours live time). The time-averaged energy spectrum,
measured between 225 GeV to ~1.3 TeV, is characterized by a very steep power
law (photon index of Gamma = (4.5 +- 0.3 {stat} +- 0.1 {syst}). The integral
flux above 300 GeV is ~3.4% of the Crab Nebula flux and shows no evidence for
any variations, on any time scale. H+K (1.45-2.45 micron) spectroscopy of PG
1553+113 was performed in March 2006 with SINFONI, an integral field
spectrometer of the ESO Very Large Telescope (VLT) in Chile. The redshift of PG
1553+113 is still unknown, as no absorption or emission lines were found.
