We have performed an analysis of the diffuse gamma-ray emission with the Fermi Large Area Telescope (LAT) in the Milky Way halo region, searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We consider both gamma rays produced directly in the dark matter annihilation/decay and produced by inverse Compton scattering of the e +/e – produced in the annihilation/decay. Conservative limits are derived requiring that the dark matter signal does not exceed the observed diffuse gamma-ray emission. A second set of more stringent limits is derived based on modeling the foreground astrophysical diffuse emission using the GALPROP code. Uncertainties in the height of the diffusive cosmic-ray halo, the distribution of the cosmic-ray sources in the Galaxy, the index of the injection cosmic-ray electron spectrum, and the column density of the interstellar gas are taken into account using a profile likelihood formalism, while the parameters governing the cosmic-ray propagation have been derived from fits to local cosmic-ray data. The resulting limits impact the range of particle masses over which dark matter thermal production in the early universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as the annihilation of dark matter.

CONSTRAINTS ON THE GALACTIC HALO DARK MATTER FROMFERMI-LAT DIFFUSE MEASUREMENTS

BALDINI, LUCA;RAZZANO, MASSIMILIANO;TINIVELLA, MARCO;
2012

Abstract

We have performed an analysis of the diffuse gamma-ray emission with the Fermi Large Area Telescope (LAT) in the Milky Way halo region, searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We consider both gamma rays produced directly in the dark matter annihilation/decay and produced by inverse Compton scattering of the e +/e – produced in the annihilation/decay. Conservative limits are derived requiring that the dark matter signal does not exceed the observed diffuse gamma-ray emission. A second set of more stringent limits is derived based on modeling the foreground astrophysical diffuse emission using the GALPROP code. Uncertainties in the height of the diffusive cosmic-ray halo, the distribution of the cosmic-ray sources in the Galaxy, the index of the injection cosmic-ray electron spectrum, and the column density of the interstellar gas are taken into account using a profile likelihood formalism, while the parameters governing the cosmic-ray propagation have been derived from fits to local cosmic-ray data. The resulting limits impact the range of particle masses over which dark matter thermal production in the early universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as the annihilation of dark matter.
M., Ackermann; M., Ajello; W. B., Atwood; Baldini, Luca; G., Barbiellini; D., Bastieri; K., Bechtol; R., Bellazzini; R. D., Blandford; E. D., Bloom; E., Bonamente; A. W., Borgland; E., Bottacini; T. J., Brandt; J., Bregeon; M., Brigida; P., Bruel; R., Buehler; S., Buson; G. A., Caliandro; R. A., Cameron; P. A., Caraveo; J. M., Casandjian; C., Cecchi; E., Charles; A., Chekhtman; J., Chiang; S., Ciprini; R., Claus; J., Cohen Tanugi; J., Conrad; A., Cuoco; S., Cutini; F., D?ammando; A., de Angelis; F., de Palma; C. D., Dermer; E. do Couto e., Silva; P. S., Drell; A., Drlica Wagner; L., Falletti; C., Favuzzi; S. J., Fegan; W. B., Focke; Y., Fukazawa; S., Funk; P., Fusco; F., Gargano; D., Gasparrini; S., Germani; N., Giglietto; F., Giordano; M., Giroletti; T., Glanzman; G., Godfrey; I. A., Grenier; S., Guiriec; M., Gustafsson; D., Hadasch; M., Hayashida; D., Horan; R. E., Hughes; M. S., Jackson; T., Jogler; G., J?hannesson; A. S., Johnson; T., Kamae; J., Kn?dlseder; M., Kuss; J., Lande; L., Latronico; A. M., Lionetto; M., Llena Garde; F., Longo; F., Loparco; B., Lott; M. N., Lovellette; P., Lubrano; M. N., Mazziotta; J. E., Mcenery; J., Mehault; P. F., Michelson; W., Mitthumsiri; T., Mizuno; A. A., Moiseev; C., Monte; M. E., Monzani; A., Morselli; I. V., Moskalenko; S., Murgia; M., Naumann Godo; J. P., Norris; E., Nuss; T., Ohsugi; M., Orienti; E., Orlando; J. F., Ormes; D., Paneque; J. H., Panetta; M., Pesce Rollins; M., Pierbattista; F., Piron; G., Pivato; H., Poon; S., Rain?; R., Rando; Razzano, Massimiliano; S., Razzaque; A., Reimer; O., Reimer; C., Romoli; C., Sbarra; J. D., Scargle; C., Sgr?; E. J., Siskind; G., Spandre; P., Spinelli; ?ukasz, Stawarz; A. W., Strong; D. J., Suson; H., Tajima; H., Takahashi; T., Tanaka; J. G., Thayer; J. B., Thayer; L., Tibaldo; Tinivella, Marco; G., Tosti; E., Troja; T. L., Usher; J., Vandenbroucke; V., Vasileiou; G., Vianello; V., Vitale; A. P., Waite; E., Wallace; K. S., Wood; M., Wood; Z., Yang; G., Zaharijas; S., Zimmer
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/226341
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