A ~200 pc-sized core of Milky Way dark matter halo constrained from the OGLE micro-lensing sky map

A ~200 pc-sized core of Milky Way dark matter halo constrained from the OGLE micro-lensing sky map by Shu-Rui Lin et al. on Monday 21 November We report the detection of a 219 $^{+10}_{-28}$ pc-sized dark matter core structure in the center of Milky Way at $68\%$ confidence level by using the micro-lensing event rate sky map data from the Optical Gravitational Lensing Experiment (OGLE) survey. For the first time, we apply the spacial information of the micro-lensing sky map and model it with the detailed Milky Way structure, the Mini Dark Matter Structure (MDMS) fraction ($f_{\rm MDMS}=\Omega_{\rm MDMS}/\Omega_{\rm DM}$) and the core size. We find that this sky map can constrain both $f_{\rm MDMS}$ and the core size simultaneously without strong degeneracy. This discovery provides not only guidance for dark matter particle models, such as self-interacting dark matter (SIDM), but also the baryonic physics of Milky Way. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.00666v2