VERITAS Observations of the gamma-Ray Binary LS I +61 303
Abstract
LS I +61 303 is one of only a few high-mass X-ray binaries currently detected at high significance in very high energy gamma-rays. The system was observed over several orbital cycles (between September 2006 and February 2007) with the VERITAS array of imaging air-Cherenkov telescopes. A signal of gamma-rays with energies above 300 GeV is found with a statistical significance of 8.4 standard deviations. The detected flux is measured to be strongly variable; the maximum flux is found during most orbital cycles at apastron. The energy spectrum for the period of maximum emission can be characterized by a power law with a photon index of Gamma=2.40+-0.16_stat+-0.2_sys and a flux above 300 GeV corresponding to 15-20% of the flux from the Crab Nebula.
Cite
@article{arxiv.0802.2363,
title = {VERITAS Observations of the gamma-Ray Binary LS I +61 303},
author = {V. A. Acciari and M. Beilicke and G. Blaylock and S. M. Bradbury and J. H. Buckley and V. Bugaev and Y. Butt and K. L. Byrum and O. Celik and A. Cesarini and L. Ciupik and Y. C. K. Chow and P. Cogan and P. Colin and W. Cui and M. K. Daniel and C. Duke and T. Ergin and A. D. Falcone and S. J. Fegan and J. P. Finley and P. Fortin and L. F. Fortson and D. Gall and K. Gibbs and G. H. Gillanders and J. Grube R. Guenette and D. Hanna and E. Hays and J. Holder and D. Horan and S. B. Hughes and C. M. Hui and T. B. Humensky and P. Kaaret and D. B. Kieda and J. Kildea and A. Konopelko and H. Krawczynski and F. Krennrich and M. J. Lang and S. LeBohec and K. Lee and G. Maier and A. McCann and M. McCutcheon and J. Millis and P. Moriarty and R. Mukherjee and T. Nagai and R. A. Ong and D. Pandel and J. S. Perkins and F. Pizlo and M. Pohl and J. Quinn and K. Ragan and P. T. Reynolds and H. J. Rose and M. Schroedter and G. H. Sembroski and A. W. Smith and D. Steele and S. P. Swordy and J. A. Toner and L. Valcarcel and V. V. Vassiliev and R. Wagner and S. P. Wakely and J. E. Ward and T. C. Weekes and A. Weinstein and R. J. White and D. A. Williams and S. A. Wissel and M. Wood and B. Zitzer},
journal= {arXiv preprint arXiv:0802.2363},
year = {2009}
}
Comments
accepted for publication in The Astrophysical Journal