Microlens Parallax Asymmetries toward the Large Magellanic Cloud
Loading...
Date
1998-10-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
American Astronomical Society
Abstract
If the microlensing events now being detected toward the Large Magellanic Cloud (LMC) are due to lenses in the Milky Way halo, then the events should typically have asymmetries of order 1% owing to parallax from the reflex motion of the Earth. By contrast, if the lenses are in the LMC, the parallax effects should be negligible. A ground-based search for such parallax asymmetries would therefore clarify the location of the lenses. A modest effort (2 hr per night on a 1 m telescope) could measure 15 parallax asymmetries over 5 yr and therefore marginally discriminate between the halo and the LMC as the source of the lenses. A dedicated 1 m telescope would approximately double the number of measurements and would therefore clearly distinguish between the alternatives. Compared to satellite parallaxes, however, the information extracted from ground-based parallaxes is substantially less useful for understanding the nature of the halo lenses (if that is what they are). The backgrounds of asymmetries owing to binary-source and binary-lens events are estimated to be approximately 7% and 12%, respectively. These complicate the interpretation of detected parallax asymmetries, but not critically.
Description
Keywords
dark matter, Galaxy: halo, gravitational lensing, Magellanic Clouds
Citation
Andrew Gould, "Microlens Parallax Asymmetries toward the Large Magellanic Cloud ," The Astrophysical Journal 506, no. 1 (1998), doi:10.1086/306240