Speaker
Description
Gamma-ray observations have long been used to constrain the properties of dark matter (DM), with a strong focus on weakly interacting massive particles annihilating through velocity-independent processes. However, in the absence of clear-cut observational evidence for the most simple candidates, the interest in more complex DM scenarios involving a velocity-dependent cross-section has grown over the past few years. I show how to analytically evaluate the Sommerfeld-enhanced gamma-ray flux produced by DM annihilation (in both the $s$- and $p$-wave cases) from targets populated by DM subhalos. Both features (Sommerfeld enhancement and the presence of subhalos) have a crucial impact in searches for thermal DM particle candidates with masses around or beyond TeV, or scenarios with a light dark sector. I present a detailed analytical description of the phenomena at play and show how they scale with the subhalo masses and the main Sommerfeld parameters. In addition, I present the main results of the first systematic study of velocity-dependent DM annihilation in a variety of astrophysical objects, not only including the well-studied Milky Way dwarf satellite galaxies but nearby dwarf irregular galaxies and local galaxy clusters as well.
Based on arXiv:2203.16491 and arXiv:2203.16440.
