專題演講 Seminar

Title

Dark Matter spikes around Sgr A* in gamma-rays

Speaker

Dr. Divya Sachdeva (Laboratoire de Physique de l'Ecole Normale Supérieure)

Abstract

We analyzed H.E.S.S. gamma-ray observations of Sgr A* to set new limits on the Dark Matter (DM) annihilation cross-section. The supermassive black hole (SMBH) at the galactic center, Sgr A*, has had the time to potentially accumulate DM in its vicinity, forming a 'spike' that could generate significant annihilation signals. Therefore, it's crucial to examine the impact of uncertainties in the DM halo profile near the galactic center. In this talk, I'll quantify how our limits depend on two key uncertainties: i) variations in the DM halo profile, from peaked to cored, and ii) the shape of the DM spike around Sgr A*, which is dynamically influenced by the nuclear star cluster. Notably, for peaked halo profiles, our constraints represent some of the most robust for DM masses above a few TeV.

Language

演講語言 (Language): in English

Hosted by

吳建宏 研究員
Ng, Kin-Wang / Research Fellow