Multimessenger study of the dark matter interpretation of the Fermi-LAT Galactic center excess

Compelling gravitational evidence has been observed for the existence of dark matter which is five times more abundant than the baryonic one. However, the exact particle nature of dark matter remains still a mystery. | will focus the seminar on the indirect detection technique which seeks to detect the rarest cosmic rays and radiation (e.g. gamma rays) generated from dark matter annihilation or decay in space. An excess of gamma rays in the data measured by the Fermi Large Area Telescope from the Galactic center region is one of the most intriguing mysteries in Astroparticle Physics that could be associated to a dark matter signal. The Galactic center excess (GCE), has been measured with respect to different interstellar emission models, source catalogs, data selections and techniques. Although several proposed interpretations have appeared in the literature, there are no firm conclusions as to its origin.

In this presentation | will show the results obtained for the GCE by using 11 years of Fermi-LAT data, state of the art interstellar emission models, and the newest 4FGL source catalog to provide precise measurements of the energy spectrum, spatial morphology, position, and sphericity of the GCE. I will also present constraints for the interpretation as dark matter particle interactions using the GCE, a gamma-ray analysis of dwarf spheroidal galaxies with LAT data and AMS-02 cosmic-ray antiprotons and positrons flux data.

Finally, I will discuss the dark matter interpretation of the GCE in the context of the simplest model beyond the Standard Model with a dark matter candidate. I will show how much we can learn by combining the results found with cosmic particle fluxes and the precise measurements from cosmology with the constraints coming from direct detection and collider experiments.

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