Galactic merger implications for eccentric nuclear discs: a mechanism for disc alignment
Abstract
The nucleus of our nearest, large galactic neighbour, M31, contains an eccentric nuclear disc - a disc of stars on eccentric, apsidally aligned orbits around a supermassive black hole (SMBH). Previous studies of eccentric nuclear discs considered only an isolated disc, and did not study their dynamics under galaxy mergers (particularly a perturbing SMBH). Here, we present the first study of how eccentric discs are affected by a galactic merger. We perform N-body simulations to study the disc under a range of different possible SMBH initial conditions. A second SMBH in the disc always disrupts it, but more distant SMBHs can shut off differential precession and stabilize the disc. This results in a more aligned disc, nearly uniform eccentricity profile, and suppression of tidal disruption events compared to the isolated disc. We also discuss implications of our work for the presence of a secondary SMBH in M31.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2021
- DOI:
- 10.1093/mnras/stab552
- arXiv:
- arXiv:2010.15957
- Bibcode:
- 2021MNRAS.503.2713R
- Keywords:
-
- black hole physics;
- galaxies: nuclei;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 14 pages, 20 figures (19 in main text, 1 in Appendix), submitted to MNRAS