Implication of spin constraints by the Event Horizon Telescope on stellar orbits in the Galactic Center

Abstract

The center of the Milky Way hosts the closest supermassive black hole, SgrA${}^{\ast }$. Decades of near-infrared observations of our Galactic Center have shown the presence of a small population of stars (the so called S-star cluster) orbiting SgrA${}^{\ast }$, which were recently reported to be arranged in two orthogonal disks. In this case, the timescale for Lense-Thirring precession of S-stars should be longer than their age, implying a low spin for SgrA${}^{\ast }$. In contrast, the recent results by the Event Horizon Telescope favor a highly-spinning SgrA${}^{\ast }$, which seem to suggest that the S-stars could not be arranged in disks. Alternatively, the spin of SgrA${}^{\ast }$ must be small, suggesting that the models for its observed image are incomplete.

4 pages, 3 figures, accepted by ApJ Letters

References in corpus (12)

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