Exploring the galactic center through gravitational microlensing: Prospects and possibilities with next-generation infrared telescopes

Abstract

We aim to present a solution to the lack of observational support to our theoretical model of the Supermassive Black Hole (SMBH) and the Galactic Center (GC). To do so, we revisit the abundance of microlensing events produced by the SMBH at the GC as a fixed lens, based on the methods given by Alexander & Loeb 2001 (AL01). By applying updated observational constraints for the distribution of stars within a few arcseconds of the SMBH, we estimate the number of lensing events of distant background sources by the SMBH alone or by it and secondary stellar lenses that lie within the GC. We find our new results to be generally consistent with AL01. We predict that in any snapshot of the central ~1 region taken with a modern detection threshold of 27-28 mag, ~10 microlensed background sources will be amplified for more than 500% in brightness. As more potential microlensing events in the GC are being identified by K-band surveys with a much higher precision than previous speckled observations, we would be able to test our predictions and offer validations on the theoretical models of GC and the SMBH.