Ponente
Descripción
Under the hypothesis that thermal relic particles populate the dark matter halo of the Milky Way, strong indirect signals in cosmic radiation are expected from the regions where the dark matter density is high. In particular, the Galactic Center is potentially hosting the largest indirect signal from dark matter pair-annihilation (or decay), which in many theoretically well-motivated models would produce gamma rays as their final states. More than a decade ago, an unexpected gamma-ray component over astrophysical backgrounds was detected at GeV energies towards the Galactic Center in the data of the Fermi Large Area Telescope. Initially, this excess was considered to be hinting at GeV thermal relics annihilating in the Galactic dark matter halo. However, by using the most advanced analysis techniques and models for the astrophysical backgrounds, recent works have demonstrated that the excess is better explained by a population of millisecond pulsar-like sources in the Galactic bulge. Building on the preference for an explanation in terms of a dim millisecond pulsar bulge population, we present new, strong constraints on thermal relic dark matter that robustly account for and mitigate astrophysical modelling uncertainties of gamma-ray emission in the inner Galaxy. This is achieved by combining adaptive template fitting and pixel count statistical methods to assess the role of sub-threshold point sources in the observed gamma-ray counts, while minimising the mis-modelling of Galactic diffuse emission backgrounds.
