Microlensing of Globular Clusters as a Probe of Galactic Structure

Abstract

The spatial distribution of compact dark matter in our Galaxy can be determined in a few years of monitoring Galactic globular clusters for microlensing. Globular clusters are the only dense fields of stars distributed throughout the three-dimensional halo and hence are uniquely suited to probe its structure. The microlensing optical depths towards different clusters have varying contributions from the thin disk, thick disk, bulge, and halo of the Galaxy. Although measuring individual optical depths to all the clusters is a daunting task, we show that interesting Galactic structure information can be extracted with as few as $40$--$120$ events in total for the entire globular cluster system (observable with 2--5 years of monitoring). The globular cluster microlensing is particularly sensitive to the core radius of the halo mass distribution and to the scale length, surface mass density, and radial scale height variations of the thin disk.

14 pages, 1 figure. Submitted to ApJ Letters. Uses aastex macros

References in corpus (2)

• Evidence for an Intervening Stellar Population Toward the Large Magellanic Cloud
• The Maximum Optical Depth Towards Bulge Stars From Axisymmetric Models of the Milky Way

Cited by in corpus (5)

• Flattened Galactic Haloes and Baryonic Dark Matter
• Detection of IMBHs from microlensing in globular clusters
• Constraining Black Hole Populations in Globular Clusters using Microlensing: Application to Omega Centauri
• Galactic globular clusters contribution to microlensing events?
• Pixel lensing observations towards globular clusters