2004/10/12 by Edward A. Baltz
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/428751
published as Astrophys.J. 624 (2005) 168-177 · 10 pages, 4 figures, 2 tables
arxiv created 2004/10/12 · openalex publication_date 2005/04/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
The Andromeda galaxy (M31) is the closest large galaxy to the Milky Way, and thus it is an important laboratory for studying massive dark objects in galactic halos by gravitational microlensing. Such studies strongly complement the studies of the Milky Way halo using the Large and Small Magellanic Clouds. We consider the possibilities for microlensing surveys of M31 using the next generation of wide-field imaging telescopes with fields of view in the square-degree range. We consider proposals for such imagers both on the ground and in space. For concreteness, we specialize to the Supernova/Acceleration Probe proposal for a space telescope and the Large Synoptic Survey Telescope proposal for a ground-based telescope. We find that a modest space-based survey of 50 visits of 1 hr each is considerably better than current ground-based surveys covering 5 years. Crucially, systematic effects can be considerably better controlled with a space telescope because of both the infrared sensitivity and the angular resolution. To be competitive, 8 m class wide-field ground-based imagers must take exposures of several hundred seconds with several days' cadence.