SEMINAR

井上開輝 (近畿大学)

It has been known that cold dark matter theory conflicts with observation on scales smaller than 10kpc. For instance, the number of dwarf galaxy in the Local Group is far smaller than the number of subhalos predicted in CDM models. If CDM dominates matter in our universe, we expect that many dark dwarf galaxies at a cosmological distance remain to be discovered. However, they are too faint to directly observe their emission with current ground or space telescopes. Gravitational lensing is a powerful tool for finding such dark dwarf galaxies: we can measure matter fluctuations (baryon plus dark matter) on small scales from strongly lensed images. The signature of gravitational perturbations due to subhalos or halos and voids in the line of sight appears as anomaly in flux ratios or astrometric shifts in lensed images. I review some our results on dark matter constraints and recent results on possible dark dwarf galaxies in some strongly lensed systems from ALMA observations. I will also explain about our current and future projects using ALMA.

日時: 9/6 15:00-
場所: 31号館401