A spherical-symmetric gamma-ray emission from {the inner region of the Galaxy (at least up to roughly 10° in latitude and longitude)} has been recently identified in Fermi-LAT data, and initially associated to dark matter particle annihilations. Guided by the evidence for a high gas density in the inner kpc of the Galaxy correlated with a very large Supernova rate, and hence with ongoing cosmic-ray acceleration, we investigate instead the possibility of addressing this excess in terms of ordinary cosmic-ray sources and standard steady-state diffusion. We {alter the source term, and consistently the correlated gamma-ray emissions, in the context of a template-fitting analysis. We focus on a region of interest (ROI) defined as: |l| < 20°; 2° < |b| < 20°, with l and b the Galactic longitude and latitude coordinates.} We analyze in detail the overall goodness of the fit of our framework, and perform a detailed direct comparison against data examining profiles in different directions. Remarkably, the test statistic of the fit related to our scenario turns out to be as good as the Dark Matter one in the ROI here considered.
Towards a realistic astrophysical interpretation of the gamma-ray Galactic center excess / Gaggero, D.; Taoso, M.; Urbano, A.; Valli, M.; Ullio, P.. - In: JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS. - ISSN 1475-7516. - 2015:12(2015). [10.1088/1475-7516/2015/12/056]
Towards a realistic astrophysical interpretation of the gamma-ray Galactic center excess
Urbano A.;
2015
Abstract
A spherical-symmetric gamma-ray emission from {the inner region of the Galaxy (at least up to roughly 10° in latitude and longitude)} has been recently identified in Fermi-LAT data, and initially associated to dark matter particle annihilations. Guided by the evidence for a high gas density in the inner kpc of the Galaxy correlated with a very large Supernova rate, and hence with ongoing cosmic-ray acceleration, we investigate instead the possibility of addressing this excess in terms of ordinary cosmic-ray sources and standard steady-state diffusion. We {alter the source term, and consistently the correlated gamma-ray emissions, in the context of a template-fitting analysis. We focus on a region of interest (ROI) defined as: |l| < 20°; 2° < |b| < 20°, with l and b the Galactic longitude and latitude coordinates.} We analyze in detail the overall goodness of the fit of our framework, and perform a detailed direct comparison against data examining profiles in different directions. Remarkably, the test statistic of the fit related to our scenario turns out to be as good as the Dark Matter one in the ROI here considered.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.