Can gravitational microlensing detect extragalactic exoplanets? Self-lensing models of the Small Magellanic Cloud

Przemek Mroz, Radoslaw Poleski
(Submitted on 11 Dec 2017)

We use three-dimensional distributions of classical Cepheids and RR Lyrae stars in the Small Magellanic Cloud (SMC) to model the stellar density distribution of a young and old stellar population in that galaxy. We use these models to estimate the microlensing self-lensing optical depth to the SMC, which is in excellent agreement with the observations. Thus, we estimate the total stellar mass of the SMC of about 1.0 x 10^9 MSun under assumption that all microlensing events toward this galaxy are caused by self-lensing. We also calculate the expected event rates and estimate that future large-scale surveys, like the Large Synoptic Survey Telescope (LSST), will be able to detect up to a few dozen microlensing events in the SMC annually. If the planet frequency in the SMC is similar to that in the Milky Way, a few extragalactic planets can be detected over the course of the LSST survey, provided significant changes in the SMC observing strategy are devised. A relatively small investment of LSST resources can give us a unique probe of the population of extragalactic exoplanets.

Comments:    submitted to ApJ
Subjects:    Earth and Planetary Astrophysics (astro-ph.EP)
Cite as:    arXiv:1712.03986 [astro-ph.EP] (or arXiv:1712.03986v1 [astro-ph.EP] for this version)
Submission history
From: Przemek Mroz
[v1] Mon, 11 Dec 2017 19:01:14 GMT (658kb,D)
https://arxiv.org/abs/1712.03986