Observations of the shell-type SNR Cassiopeia A at TeV energies with VERITAS
Abstract
We report on observations of very high-energy gamma rays from the shell-type supernova remnant Cassiopeia A with the VERITAS stereoscopic array of four imaging atmospheric Cherenkov telescopes in Arizona. The total exposure time for these observations is 22 hours, accumulated between September and November of 2007. The gamma-ray source associated with the SNR Cassiopeia A was detected above 200 GeV with a statistical significance of 8.3 s.d. The estimated integral flux for this gamma-ray source is about 3% of the Crab-Nebula flux. The photon spectrum is compatible with a power law dN/dE ~ E^(-Gamma) with an index Gamma = 2.61 +/- 0.24(stat) +/- 0.2(sys). The data are consistent with a point-like source. We provide a detailed description of the analysis results, and discuss physical mechanisms that may be responsible for the observed gamma-ray emission.
Cite
@article{arxiv.1002.2974,
title = {Observations of the shell-type SNR Cassiopeia A at TeV energies with VERITAS},
author = {The VERITAS Collaboration and V. A. Acciari and E. Aliu and T. Arlen and T. Aune and M. Bautista and M. Beilicke and W. Benbow and D. Boltuch and S. M. Bradbury and J. H. Buckley and V. Bugaev and Y. Butt and K. Byrum and A. Cannon and A. Cesarini and Y. C. Chow and L. Ciupik and P. Cogan and W. Cui and R. Dickherber and C. Duke and T. Ergin and S. J. Fegan and J. P. Finley and G. Finnegan and P. Fortin and L. Fortson and A. Furniss and N. Galante and D. Gall and G. H. Gillanders and J. Grube and R. Guenette and G. Gyuk and D. Hanna and J. Holder and D. Huang and C. M. Hui and T. B. Humensky and P. Kaaret and N. Karlsson and M. Kertzman and D. Kieda and A. Konopelko and H. Krawczynski and F. Krennrich and M. J. Lang and S. LeBohec and G. Maier and S. McArthur and A. McCann and M. McCutcheon and J. Millis and P. Moriarty and R. A. Ong and D. Pandel and J. S. Perkins and M. Pohl and J. Quinn and K. Ragan and P. T. Reynolds and E. Roache and H. J. Rose and M. Schroedter and G. H. Sembroski and A. W. Smith and B. R. Smith and D. Steele and S. P. Swordy and M. Theiling and S. Thibadeau and A. Varlotta and V. V. Vassiliev and S. Vincent and R. G. Wagner and S. P. Wakely and J. E. Ward and T. C. Weekes and A. Weinstein and T. Weisgarber and S. Wissel and M. Wood},
journal= {arXiv preprint arXiv:1002.2974},
year = {2010}
}
Comments
27 pages, 2 figures; Accepted for publication in ApJ