A search for massive compact halo objects in our galaxy

Massive Compact Halo Objects such as brown dwarfs, Jupiters, and black holes are prime candidates to comprise the dark halo of our galaxy. Paczynski noted that these objects (dubbed MACHOs) can be detected via gravitational microlensing of stars in the Magellanic Clouds with the caveat that only about one in 106 stars will be lensed at any given time. Our group is currently involved in constucting a dedicated observing system at the Mount Stromlo Observatory in Austrilia. We will use a refurbished 1.27 meter telescope and an innovative two-color CCD camera with 3.4×107 pixels to monitor 106-107 stars in the Magellanic Clouds. During the first year of operation (1991-1992), we hope to detect (or rule out) objects in the mass range 0.001 Msolar<=M<=0.1Msolar, and after five years, we hope to have covered the range 10-6Msolar<M<~100Msolar.