Gravitational microlensing as a method of detecting disk dark matter and faint disk stars

Abstract

Gravitational microlensing of stars in the Galactic bulge is proposed as a method of probing the mass density of disk objects in the 10^-3^ to 10^-1^ M_sun _ range. A substantial rate is found if disk dark matter of this form exists, and even without any dark matter, a significant microlensing rate is found, owing to the faint low-mass disk stars which are known to exist. Such a search would provide new information on the disk dark matter question, probe the low-end stellar mass function, and also search for halo dark matter, all with rates comparable to those expected for the ongoing LMC microlensing halo dark matter searches.