Dr. Judit Perez Romero (UNG): Indirect searches for dark matter with gamma-rays: the case of galaxy clusters

Gravitational evidence at different cosmological scales hints at the existence of a dark component of the Universe, which accounts for up to 85 % of its matter density. Several theoretical particle models for dark matter (DM) predict that it weakly interacts with Standard Model particles. Among these interactions, one of the most promising channels is gamma-rays. However, despite all efforts, DM has so far eluded any clear detection. This talk will be devoted to navigating through the different DM search strategies, providing a broad overview. We will discuss the state-of-the-art and the near future of gamma-ray DM searches, covering both satellite-based and ground-based observatories, and the use of different astrophysical targets to highlight the need for complementarity between strategies.
Finally, I will focus on the science case of galaxy clusters. Galaxy clusters are the largest gravitationally bound structures in the Universe and are strongly dominated by DM. However, clusters are also expected to be cosmic-ray (CR) reservoirs, resulting in diffuse gamma-ray emission through interactions with the intra-cluster medium. The detection of diffuse gamma-ray emission from galaxy clusters, whether DM- and/or CR-induced, is one of the long-awaited milestones of the high-energy astroparticle physics community. In this talk, I will present the results of the analysis of 16 years of Fermi-LAT data in the direction of 48 galaxy clusters, and I will also discuss the prospects of the forthcoming Cherenkov Telescope Array Observatory (CTAO) for detecting diffuse gamma-ray emission from clusters.
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