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

Markus Ackermann , Marco Ajello , W. B. Atwood , Luca Baldini , Guido Barbiellini , D. Bastieri , K. Bechtol , R. Bellazzini , R. D. Blandford , E. D. Bloom , E. Bonamente , A. W. Borgland , E. Bottacini , T. J. Brandt (1) , J. Bregeon , M. Brigida , Pascal Bruel (2) , R. Buehler , S. Buson , G. A. Caliandro , R. A. Cameron , P. A. Caraveo , J. M. Casandjian (3) , C. Cecchi , E. Charles , A. Chekhtman , J. Chiang , S. Ciprini , R. Claus , J. Cohen-Tanugi (4) , 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 (2) , 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 (3) , S. Guiriec , M. Gustafsson , D. Hadasch , M. Hayashida , D. Horan (2) , R. E. Hughes , M. S. Jackson , T. Jogler , G. Jóhannesson , A. S. Johnson , T. Kamae , Jürgen Knödlseder (1) , M. Kuss , J. Lande (1) , L. Latronico , A. M. Lionetto , M. Llena Garde , F. Longo , F. Loparco , B. Lott (5) , M. N. Lovellette , P. Lubrano , M. N. Mazziotta , J. E. Mcenery , J. Mehault (4) , 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 (4) , T. Ohsugi , M. Orienti , E. Orlando , J. F. Ormes , D. Paneque , J. H. Panetta , M. Pesce-Rollins , M. Pierbattista (3) , F. Piron (4) , 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 (4) , G. Vianello , V. Vitale , A. P. Waite , E. Wallace , K. S. Wood , M. Wood , Z. Yang , G. Zaharijas , S. Zimmer

1 IRAP - Institut de recherche en astrophysique et planétologie
2 LLR - Laboratoire Leprince-Ringuet
3 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
4 LUPM - Laboratoire Univers et Particules de Montpellier
5 GLAST

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.

Mots clés: dark matter; Galaxy: halo; gamma rays: diffuse background; methods: statistical

Domaines: Phénomènes cosmiques de haute energie [astro-ph.HE]; Phénomènes cosmiques de haute energie [astro-ph.HE]

Markus Ackermann, Marco Ajello, W. B. Atwood, Luca Baldini, Guido Barbiellini, et al.. Constraints on the Galactic Halo Dark Matter from Fermi-LAT Diffuse Measurements. The Astrophysical Journal, 2012, 761, pp.91. ⟨10.1088/0004-637X/761/2/91⟩. ⟨in2p3-00772101⟩