Long-Term Observations of the Blazar Mrk 501 with the GT-48 Cherenkov Telescope

Abstract

The galaxy Mrk 501 has been monitored with the GT-48 Cherenkov telescope at the Crimean Astrophysical Observatory for 14 years (1997–2010). Very-high-energy (VHE) gamma-ray photons have been recorded from Mrk 501 with a total significance of 15σ. The arrival directions of VHE gamma-ray photons have been mapped. They have been identified with Mrk 501. The TeV fluxes from Mrk 501 are shown to be highly variable. The light curves from the data of Cherenkov telescopes and the telescopes that observed Mrk 501 at high energies (MeV and GeV) and in the X-ray and optical bands are presented. Based on the GT-48 observations, we have constructed a TeV spectrum and determined the differential spectral index. The fluxes and spectral characteristics of Mrk 501 inferred from the GT-48 observations are consistent with the data of the MAGIC and H.E.S.S. Collaborations, respectively.