Journal Article

Chromatic and spectroscopic signatures of microlensing events as a tool for the gravitational imaging of stars

David Valls-Gabaud

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 294, issue 4, pages 747-752
Published in print March 1998 | ISSN: 0035-8711
Published online March 1998 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-8711.1998.01247.x
Chromatic and spectroscopic signatures of microlensing events as a tool for the gravitational imaging of stars

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Abstract

The detection of microlensing events from stars in the Large Magellanic Cloud and in the Galactic bulge raises important constraints on the distribution of dark matter and on galactic structure, although some events may be the result of a new type of intrinsic variability. When lenses are relatively close to the sources, we predict that chromatic and spectroscopic effects are likely to appear for a significant fraction of the microlensing events. These effects are due to the differential amplification of the limb and the centre of the stellar disc, and present a systematic dependence with wavelength and time that provides an unambiguous signature of a microlensing event (as opposed to a new type of intrinsic stellar variability). We present detailed predictions of the effects, using realistic model atmospheres. The observations of these effects provide a direct constraint on stellar atmospheres, allowing a three-dimensional reconstruction or imaging of its structure, a unique tool with which to test the current models of stellar atmospheres.

Keywords: stars: atmospheres; stars: imaging; Galaxy: halo; Galaxy: stellar content; dark matter; gravitational lensing

Journal Article.  0 words. 

Subjects: Astronomy and Astrophysics

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