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Indirect Dark Matter Searches with VERITAS |
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Conference Proceedings
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Written by Matt Wood for the VERITAS Collaboration
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Monday, 31 March 2008 |
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Bulletin of the AAS (BAAS), volume 40, number 1, 2008 (18.06) If dark matter (DM) is composed of massive, weakly-interacting particles such as the neutralino predicted by supersymmetry, pair annihilation to gamma rays or secondary particles ultimately producing a continuum spectrum of gamma rays may take place in gravitationally clustered DM. Due to their large mass-to-light ratios and the absence of conventional gamma-ray sources in their vicinity, dwarf spheroidal galaxies of the Local Group are obvious targets to search for such annihilation. We report here on gamma-ray observations taken with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) during the 2007/8 season of the dwarf galaxies Ursa Minor, Draco, and Willman I and the local group galaxy M33. We discuss the implications of these measurements for models of DM clustering and DM particle properties. |
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Last Updated ( Monday, 14 April 2008 )
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VERITAS Observations of the gamma-Ray Binary LS I +61 303 |
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Science Publications
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Written by V.A. Acciari and the VERITAS Collaboration
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Tuesday, 19 February 2008 |
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The Astrophysical Journal, Volume 679, Issue 2, pp. 1427-1432. arXiv: astro-ph/0802.2363 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. Additional Information: Differential energy spectrum of VHE photons above 300 GeV for LS I +61 303 around apastron (orbital phases 0.5–0.8). Taken from Fig.2 in V.A.Acciari et al, The Astrophysical Journal, Volume 679, Issue 2, pp. 1427-1432 (arXiv:0802.2363)):
Energy dN/dE
[TeV] [cm^{-2}s^{-1}TeV^{-1}]
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0.37 2.83e-11 +- 1.14e-11
0.53 1.25e-11 +- 3.66e-12
0.74 6.70e-12 +- 1.49e-12
1.05 2.23e-12 +- 6.37e-13
1.48 1.24e-12 +- 3.17e-13
2.09 6.62e-13 +- 1.93e-13
2.99 <1.96e-13
4.18 7.00e-14 +- 3.48e-14
5.96 <4.14e-14
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Last Updated ( Wednesday, 14 January 2009 )
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Observation of gamma-ray emission from the galaxy M87 above 250 GeV with VERITAS |
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Science Publications
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Written by V.A. Acciari and the VERITAS Collaboration
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Tuesday, 19 February 2008 |
The Astrophysical Journal, Volume 679, Issue 1, pp. 397-403.
arXiv: astro-ph/0802.1951
Abstract: The multiwavelength observation of the nearby radio galaxy M87 provides a unique opportunity to study in detail processes occurring in Active Galactic Nuclei from radio waves to TeV gamma-rays. Here we report the detection of gamma-ray emission above 250 GeV from M87 in spring 2007 with the VERITAS atmospheric Cherenkov telescope array and discuss its correlation with the X-ray emission. The gamma-ray emission is measured to be point-like with an intrinsic source radius less than 4.5 arcmin. The differential energy spectrum is fitted well by a power-law function: dPhi/dE=(7.4+-1.3_{stat}+-1.5_{sys})(E/TeV)^{-2.31+-0.17_{stat}+-0.2_{sys}} 10^{-9}m^{-2}s^{-1}TeV^{-1}. We show strong evidence for a year-scale correlation between the gamma-ray flux reported by TeV experiments and the X-ray emission measured by the ASM/RXTE observatory, and discuss the possible short-time-scale variability. These results imply that the gamma-ray emission from M87 is more likely associated with the core of the galaxy than with other bright X-ray features in the jet. |
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Last Updated ( Thursday, 17 July 2008 )
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New Technology for Imaging Atmospheric Cherenkov Telescopes and Underwater Neutrino Detectors |
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Theses and Dissertations
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Written by Richard White
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Saturday, 01 December 2007 |
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New Technology for Imaging Atmospheric Cherenkov Telescopes and Underwater Neutrino Detectors Richard White Supervised by Joachim Rose Department of Physics and Astronomy, University of Leeds December 2007 |
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Last Updated ( Monday, 11 February 2008 )
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Multiwavelength Observations of the TeV Binary LS I +61 303 |
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Theses and Dissertations
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Written by Andrew Smith
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Saturday, 01 December 2007 |
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Supervisor: Dr. Stella Bradbury The University of Leeds School of Physics & Astronomy |
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Last Updated ( Friday, 12 September 2008 )
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