Very-high-energy (VHE; > 100 GeV) gamma-ray emission from the blazar RGB J2243+203 was discovered with the VERITAS Cherenkov telescope array, during the period between 2014 December 21 and 24. The VERITAS energy spectrum from this source can be fitted by a power law with a photon index of 4.6±0.5, and a flux normalization at 0.15 TeV of (6.3 ±1.1 10-10 cm-2 s-1 TeV-1 )10-2 1 1. The integrated Fermi-LAT flux from 1 to 100 GeV during the VERITAS detection is (4.1 ±0.8× 10 cm-2 s-1 ), which is an order of magnitude larger than the four-year-averaged flux in the same energy range reported in the 3FGL catalog, (4.0± 0.1× 10-9 cm-2s -1). The detection with VERITAS triggered observations in the X-ray band with the Swift-XRT. However, due to scheduling constraints Swift-XRT observations were performed 67 hr after the VERITAS detection, rather than simultaneously with the VERITAS observations. The observed X-ray energy spectrum between 2 and 10 keV can be fitted with a power law with a spectral index of 2.7±0.2, and the integrated photon flux in the same energy band is (3.6 ±0.6 10-13 cm-2 s-1 ). EBL-model-dependent upper limits of the blazar redshift have been derived. Depending on the EBL model used, the upper limit varies in the range from z < 0.9 to z < 1.1.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science