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arXiv · 2010.15957

Galactic merger implications for eccentric nuclear disks: a mechanism for disk alignment

Alexander Rodriguez·Aleksey Generozov·Ann-Marie Madigan
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Abstract

The nucleus of our nearest, large galactic neighbor, M31, contains an eccentric nuclear disk--a disk of stars on eccentric, apsidally-aligned orbits around a supermassive black hole (SMBH). Previous studies of eccentric nuclear disks considered only an isolated disk, and did not study their dynamics under galaxy mergers (particularly a perturbing SMBH). Here, we present the first study of how eccentric disks are affected by a galactic merger. We perform N-body simulations to study the disk under a range of different possible SMBH initial conditions. A second SMBH in the disk always disrupts it, but more distant SMBHs can shut off differential precession and stabilize the disk. This results in a more aligned disk, nearly uniform eccentricity profile, and suppression of tidal disruption events compared to the isolated disk. We also discuss implications of our work for the presence of a secondary SMBH in M31.

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Alexander Rodriguez, Aleksey Generozov, Ann-Marie Madigan. 2020-10-29. Galactic merger implications for eccentric nuclear disks: a mechanism for disk alignment. https://doi.org/10.1093/mnras/stab552

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