Interacting dark matter contribution to the galactic 511 keV gamma ray emission: constraining the morphology with INTEGRAL/SPI observations
- Department of Physics, McGill University, 3600 Rue University, Montréal, Québec, H3A 2T8 Canada (Canada)
- Institut de Planétologie et d'Astrophysique de Grenoble, BP 53, 38041 Grenoble Cedex 9 (France)
We compare the full-sky morphology of the 511 keV gamma ray excess measured by the INTEGRAL/SPI experiment to predictions of models based on dark matter (DM) scatterings that produce low-energy positrons: either MeV-scale DM that annihilates directly into e{sup +}e{sup −} pairs, or heavy DM that inelastically scatters into an excited state (XDM) followed by decay into e{sup +}e{sup −} and the ground state. By direct comparison to the data, we find that such explanations are consistent with dark matter halo profiles predicted by numerical many-body simulations for a Milky Way-like galaxy. Our results favor an Einasto profile over the cuspier NFW distribution and exclude decaying dark matter scenarios whose predicted spatial distribution is too broad. We obtain a good fit to the shape of the signal using six fewer degrees of freedom than previous empirical fits to the 511 keV data. We find that the ratio of flux at Earth from the galactic bulge to that of the disk is between 1.9 and 2.4, taking into account that 73% of the disk contribution may be attributed to the beta decay of radioactive {sup 26}Al.
- OSTI ID:
- 22280120
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2012, Issue 04; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
Similar Records
The INTEGRAL/SPI 511 keV Signal from Hidden Valleys
The 511 keV emission from positron annihilation in the Galaxy