Paper: astro-ph/0507265
Date: Mon, 11 Jul 2005 20:06:07 GMT (58kb)

Title: Microlensing of Circumstellar Disks

Authors: Zheng Zheng and Brice M\'enard (IAS)
Comments: 9 pages, 7 figures. Submitted to ApJ
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We investigate the microlensing effects on a source star surrounded by a
circumstellar disk, as a function of wavelength. In the mid- and far-infrared,
where the emission of the system is dominated by the cold dusty disk, the
microlensing light curve encodes the geometry and surface brightness profile of
the disk. For a system located at the Galactic center, we find typical
magnifications to be of order 10-20%, and the event lasts over one year. At
around 20 microns, where the emission for the star and the disk are comparable,
the difference in the emission areas results in a chromatic microlensing event.
Finally, in the near-infrared and visible, where the emission of the star
dominates, the fraction of star light directly reflected by the disk slightly
modifies the light curve of the system which is no longer that of a point
source. In each case, the corresponding light curve can be used to probe some
of the disk properties. A fraction of 0.1% to 1% optical microlensing events
are expected to be associated with circumstellar disk systems. We show that the
lensing signal of the disk can be detected with sparse follow-up observations
of the next generation space telescopes. While direct imaging studies of
circumstellar disks are limited to the solar neighborhood, this microlensing
technique can probe very distant disk systems living in various environments
and has the potential to reveal a larger diversity of circumstellar disks.

\\ ( http://arXiv.org/abs/astro-ph/0507265 , 58kb)