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 FROM FERMI-LAT DIFFUSE MEASUREMENTS / Ackermann M; Ajello M; Atwood WB; Baldini L; Barbiellini G; Bastieri D; Bechtol K; Bellazzini R; Blandford RD; Bloom ED; Bonamente E; Borgland AW; Bottacini E; Brandt TJ; Bregeon J; Brigida M; Bruel P; Buehler R; Buson S; Caliandro GA; Cameron RA; Caraveo PA; Casandjian JM; Cecchi C; Charles E; Chekhtman A; Chiang J; Ciprini S; Claus R; Cohen-Tanugi J; Conrad J; Cuoco A; Cutini S; DAmmando F; de Angelis A; de Palma F; Dermer CD; Silva EDE; Drell PS; Drlica-Wagner A; Falletti L; Favuzzi C; Fegan SJ; Focke WB; Fukazawa Y; Funk S; Fusco P; Gargano F; Gasparrini D; Germani S; Giglietto N; Giordano F; Giroletti M; Glanzman T; Godfrey G; Grenier IA; Guiriec S; Gustafsson M; Hadasch D; Hayashida M; Horan D; Hughes RE; Jackson MS; Jogler T; Johannesson G; Johnson AS; Kamae T; Knodlseder J; Kuss M; Lande J; Latronico L; Lionetto AM; Garde ML; Longo F; Loparco F; Lott B; Lovellette MN; Lubrano P; Mazziotta MN; McEnery JE; Mehault J; Michelson PF; Mitthumsiri W; Mizuno T; Moiseev AA; Monte C; Monzani ME; Morselli A; Moskalenko IV; Murgia S; Naumann-Godo M; Norris JP; Nuss E; Ohsugi T; Orienti M; Orlando E; Ormes JF; Paneque D; Panetta JH; Pesce-Rollins M; Pierbattista M; Piron F; Pivato G; Poon H; Raino S; Rando R; Razzano M; Razzaque S; Reimer A; Reimer O; Romoli C; Sbarra C; Scargle JD; Sgro C; Siskind EJ; Spandre G; Spinelli P; Stawarz L; Strong AW; Suson DJ; Tajima H; Takahashi H; Tanaka T; Thayer JG; Thayer JB; Tibaldo L; Tinivella M; Tosti G; Troja E; Usher TL; Vandenbroucke J; Vasileiou V; Vianello G; Vitale V; Waite AP; Wallace E; Wood KS; Wood M; Yang Z; Zaharijas G; Zimmer S. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - STAMPA. - 761:2(2012), pp. 91.91-91.108. [10.1088/0004-637X/761/2/91]
CONSTRAINTS ON THE GALACTIC HALO DARK MATTER FROM FERMI-LAT DIFFUSE MEASUREMENTS
D'AMMANDO, FILIPPO;
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
