Colloquium on Dec. 17, 2020

Dwarf galaxies as probes of the nature of dark matter

Speaker: Kohei Hayashi (Tohoku University)

Venue: Video Conference

Time: 14:30 PM, Thusday, Dec. 17, 2020

Abstract:

Dark matter is now known to be the vital ingredient for the growth of structure in the Universe, while its nature remains a mystery. The dwarf galaxies are excellent laboratories to study the nature of dark matter as they are largely dark-matter dominated systems. In particular, revealing their dark matter distributions is of importance in testing dark matter models.In this work, we estimate the dark matter distributions in the luminous dwarf satellites through our dynamical analysis of their stellar-kinematic data and find the diversity of the inner slopes in their dark matter halos. Interestingly, this diversity can be explained if we consider the impact of baryonic feedback on the central dark matter densities predicted by recent dark matter and hydrodynamical simulations. Thus, to set constraints on the nature of dark matter, it is necessary to look at much fainter dwarfs, namely ultra-faint dwarfs, which are believed to have held original dark matter density profiles.In this talk, I will show the inferred dark matter density profiles in the Galactic luminous dSphs, and also present new constraints on alternative dark matter models from the ultra-faint dwarf galaxies. Then, I will introduce the feasibility and future prospects for dark matter studies with Subaru-PFS survey.

Report PPT:  SWIFAR_Kohei Hayashi.pdf