Author Info

V. A. Acciari, Harvard-Smithsonian Center for Astrophysics
T. Arlen, University of California - Los Angeles
T. Aune, University of California - Santa Cruz
M. Beilicke, Washington University
W. Benbow, Harvard-Smithsonian Center for Astrophysics
D. Boltuch, University of Delaware
S. M. Bradbury, University of Leeds
J. H. Buckley, Washington University
V. Bugaev, Washington University
K. Byrum, Argonne National Laboratory
A. Cannon, University College Dublin
A. Cesarini, National University of Ireland Galway
Jodi L. Christiansen, California Polytechnic State University - San Luis ObispoFollow
L. Ciupik, Adler Planetarium and Astronomy Museum
W. Cui, Purdue University
R. Dickherber, Washington University
C. Duke, Grinnell College
J. P. Finley, Purdue University
G. Finnegan, University of Utah
A. Furniss, University of California - Santa Cruz
N. Galante, Harvard-Smithsonian Center for Astrophysics
S. Godambe, University of Utah
J. Grube, Adler Planetarium and Astronomy Museum
R. Guenette, McGill University
G. Gyuk, Adler Planetarium and Astronomy Museum
D. Hanna, McGill University
J. Holder, University of Delaware
C. M. Hui, University of Utah
T. B. Humensky, University of Chicago
A. Imran, Iowa State University
P. Kaaret, University of Iowa
N. Karlsson, University of Minnesota - Minneapolis
M. Kertzman, DePauw University
D. Kieda, University of Utah
A. Konopelko, Pittsburg State University
H. Krawczynski, Washington University
F. Krennrich, Iowa State University
G. Maier, Platanenallee
S. McArthur, Washington University
A. McCann, McGill University
M. McCutcheon, McGill University
P. Moriarty, Galway-Mayo Institute of Technology
R. A. Ong, University of California - Los Angeles
A. N. Otte, University of California - Santa Cruz
D. Pandel, University of Iowa
J. S. Perkins, Harvard-Smithsonian Center for Astrophysics
M. Pohl, Platanenallee
J. Quinn, University College Dublin
K. Ragan, McGill University
L. C. Reyes, University of Chicago
P. T. Reynolds, University of Chicago
E. Roache, Harvard-Smithsonian Center for Astrophysics
H. J. Rose, University of Leeds
M. Schroedter, Iowa State University
G. H. Sembroski, Purdue University
G. D. Senturk, Columbia University
A. W. Smith, Argonne National University
D. Steele, Adler Planetarium and Astronomy Museum
S. P. Swordy, University of Chicago
G. Tesic, McGill University
M. Theiling, Harvard-Smithsonian Center for Astrophysics
S. Thibadeau, Washington University
A. Varlotta, Purdue University
V. V. Vassiliev, University of California - Los Angeles
S. Vincent, University of Utah
R. G. Wagner, Argonne National University
S. P. Wakely, University of Chicago
J. E. Ward, University College Dublin
T. C. Weekes, Harvard-Smithsonian Center for Astrophysics
A. Weinstein, University of California - Los Angeles
T. Weisgarber, University of Chicago
D. A. Williams, University of California - Santa Cruz
S. Wissel, University of Chicago
B. Zitzer, Purdue University

Abstract

Indirect dark matter searches with ground-based gamma-ray observatories provide an alternative for identifying the particle nature of dark matter that is complementary to that of direct search or accelerator production experiments. We present the results of observations of the dwarf spheroidal galaxies Draco, Ursa Minor, Bootes 1, and Willman 1 conducted by the Very Energetic Radiation Imaging Telescope Array System (VERITAS). These galaxies are nearby dark matter dominated objects located at a typical distance of several tens of kiloparsecs for which there are good measurements of the dark matter density profile from stellar velocity measurements. Since the conventional astrophysical background of very high energy gamma rays from these objects appears to be negligible, they are good targets to search for the secondary gamma-ray photons produced by interacting or decaying dark matter particles. No significant gamma-ray flux above 200 GeV was detected from these four dwarf galaxies for a typical exposure of ∼20 hr. The 95% confidence upper limits on the integral gamma-ray flux are in the −1 range (0.4–2.2) × 10−12 photons cm−2 s-1. We interpret this limiting flux in the context of pair annihilation of weakly interacting massive particles (WIMPs) and derive constraints on the thermally averaged product of 3 −1 the total self-annihilation cross section and the relative velocity of the WIMPs ((σv) < 10−23cm3s-1 for mχ > 300 GeV c−2). This limit is obtained under conservative assumptions regarding the dark matter distribution in dwarf galaxies and is approximately 3 orders of magnitude above the generic theoretical prediction for WIMPs in the minimal supersymmetric standard model framework. However, significant uncertainty exists in the dark matter distribution as well as the neutralino cross sections which under favorable assumptions could further lower this limit.

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Physics

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URL: http://digitalcommons.calpoly.edu/phy_fac/373