APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Kohei Hattori (NAOJ / Institute of Statistical Mathematics)
Title: Finding completely disrupted satellites that merged to the ancient Milky Way
Date (JST): Thu, May 19, 2022, 11:00 - 12:00
Place: Zoom
Abstract: In the standard Lambda-CDM cosmology, it is believed that the Milky Way was formed through hierarchical mergers of smaller systems, such as dwarf galaxies. When a dwarf galaxy merges to the Milky Way and is disrupted, the member stars are stripped from the progenitor. Because those stars originated from the same dwarf galaxy have similar dynamical properties, we can recover the disrupted dwarf galaxies by a clustering analysis of the orbital properties of stars. In this talk, I will talk about our clustering analysis of chemically peculiar halo stars in the Solar neighborhood. We found several groups of stars with similar orbits and chemistry, which we interpret as the remnants of the completely disrupted dwarf galaxies.