Hunting for ultralight fields with galactic dynamics

by Dr. Kfir Blum

Weizmann Institute

at Particles and Fields Seminar

Mon, 09 Nov 2020, 14:00
Zoom

Abstract

Ultralight dark matter (ULDM) would form cores at the centres of galaxies, allowing to detect (or constrain) the lowest allowed mass for dark matter using gravity alone. Numerical simulations of ULDM galactic halos found empirical scaling relations between the mass of the host galaxy and the mass of the core. We show that this empirical result amounts to an equality between the specific kinetic energy in the core and in the host halo. Contrasting this prediction to the measured rotation curves of low surface-brightness galaxies, we show that ULDM in the mass range m < 10^-21eV, which has been invoked as a possible solution of small-scale puzzles of LCDM, is in tension with the data. We discuss additional phenomena including gravitational lensing, stellar dynamics near supermassive black holes, and runaway stars in dwarf galaxies, that probe ULDM from m ~ 10^-25eV up to m ~ 10^-18eV even if it makes up only a fraction of the total DM density.

Zoom link:

https://us02web.zoom.us/j/84482452180?pwd=dHUwQk5mb3h6bWpBSk53WjE0RnFzZz09

Created on 04-11-2020 by Palti, Eran (palti)
Updaded on 04-11-2020 by Palti, Eran (palti)