Monitoring lensed starlight emitted close to the Galactic Center

Abstract

We describe the feasibility of detecting the gravitational deflection of light emitted by stars moving under the influence of the massive object at the Galactic center. Light emitted by a star orbiting behind the central mass has a smaller impact parameter than the star itself, and suffers the effect of gravitational lensing, providing a closer probe of the central mass distribution and hence a stricter test of the black hole hypothesis. A mass of $4.3\times 10^6{M}_{\odot }$ causes a $0.1-2\mathrm{mas}$ deviation in the apparent position of orbiting stars projected within $10^{\circ }$ of the line of sight to the galactic center. In addtion, we may uniquely constrain the distance to the center of the galaxy because lensing deflections constrain the ratio $\rg/R_{0}$ of the Schwarzschild radius to the distance to the black hole, $R_o$, whereas the ratio $\rg/R_{o}^{3}$ is obtained by fitting the orbit.

4 pages, 3 figures, submitted to MNRAS

References in corpus (5)

• The Stellar Cusp Around the Supermassive Black Hole in the Galactic Center
• Stellar dynamics in the central arcsecond of our galaxy
• A Geometric Determination of the Distance to the Galactic Center
• Limits on the Short Term Variability of Sagittarius A* in the Near-Infrared
• High Precision Stellar Radial Velocities in the Galactic Center

Cited by in corpus (10)

• Monitoring stellar orbits around the Massive Black Hole in the Galactic Center
• Gravitational Lensing by Black Holes
• Stellar Processes Near the Massive Black Hole in the Galactic Center
• Stellar Dynamics and Stellar Phenomena Near A Massive Black Hole
• What is limiting near-infrared astrometry in the Galactic Center?
• Gravitational Lensing of stars in the central arcsecond of our Galaxy
• The Galactic Center as a laboratory for theories of gravity and dark matter
• Dark matter concentrations in galactic nuclei according to polytropic models
• Dark halo microphysics and massive black hole scaling relations in galaxies
• Analytic Post-Newtonian Astrometric and Spectroscopic Models of Orbits around Black Holes