Microlensing of an Elliptical Source by a Point Mass
Abstract
We present an efficient method for computing lightcurves of an elliptical source which is microlensed by a point mass. The amplification of an extended source involves a two-dimensional integral over its surface brightness distribution. We show that for a general surface brightness profile with an elliptical symmetry, this integral can be reduced to one dimension. We derive analytical results for the entire lightcurve in the limit of low (e.g. planetary) mass lenses, and for the wings of all microlensing lightcurves in general. In both cases, the lightcurve carries information about deviations of the source from elliptical symmetry, e.g. due to spots. The method is used to find the amplification of a circular red giant photosphere and an inclined accretion disk. We demonstrate that microlensing of an emission line from a disk can be used to infer the disk velocity structure and surface brightness profile.
Cite
@article{arxiv.astro-ph/9702097,
title = {Microlensing of an Elliptical Source by a Point Mass},
author = {David Heyrovsky and Abraham Loeb},
journal= {arXiv preprint arXiv:astro-ph/9702097},
year = {2009}
}
Comments
27 pages, 10 figures, to appear in ApJ, November 1997. Slight change in notation, added illustration of microlensing-induced redshift variation, minor changes in text