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Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


Astrophysics and Astronomy | Cosmology, Relativity, and Gravity | External Galaxies | Other Astrophysics and Astronomy | Stars, Interstellar Medium and the Galaxy

Publication Details

Astrophysical Journal Letters


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 . The integrated Fermi-LAT flux from 1 to 100 GeV during the VERITAS detection is , which is an order of magnitude larger than the four-year-averaged flux in the same energy range reported in the 3FGL catalog, (). 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 . 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 to z .