Detection of Very High Energy Radiation from the BL Lacertae Object PG 1553+113 with the MAGIC Telescope
Abstract
In 2005 and 2006, the MAGIC telescope observed very high energy gamma-ray emission from the distant BL Lac object PG 1553+113. The overall significance of the signal was 8.8 σ for 18.8 hr of observation time. The light curve shows no significant flux variations on a daily timescale; the flux level during 2005 was, however, significantly higher compared to 2006. The differential energy spectrum between ~90 and 500 GeV is well described by a power law with photon index Γ=4.2+/-0.3. The combined 2005 and 2006 energy spectrum provides an upper limit of z=0.74 on the redshift of the object.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2007
- DOI:
- 10.1086/511384
- arXiv:
- arXiv:astro-ph/0606161
- Bibcode:
- 2007ApJ...654L.119A
- Keywords:
-
- BL Lacertae objects: individual (PG 1553+113);
- Gamma Rays: Observations;
- Astrophysics
- E-Print:
- version accepted for publication in ApJ Letters, 6 pages, 4 figures Removed unnecessary compendium