1205.6474 (The Fermi-LAT collaboration: M. Ackermann et al.)

Constraints on the Galactic Halo Dark Matter from Fermi-LAT Diffuse Measurements    [PDF]

The Fermi-LAT collaboration: M. Ackermann, M. Ajello, W. B. Atwood, L. Baldini, 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. Jóhannesson, A. S. Johnson, T. Kamae, J. Knödlseder, 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. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, C. Romoli, C. Sbarra, J. D. Scargle, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, Łukasz Stawarz, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, L. Tibaldo, M. Tinivella, 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

We have performed an analysis of the diffuse gamma-ray emission with the Fermi Large Area Telescope 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 annihilation of dark matter.

View original: http://arxiv.org/abs/1205.6474