The Doubling of Stellar Black Hole Nuclei

Abstract

It is strongly believed that Andromeda's double nucleus signals a disk of stars revolving around its central super-massive black hole on eccentric Keplerian orbits with nearly aligned apsides. A self-consistent stellar dynamical origin for such apparently long-lived alignment has so far been lacking, with indications that cluster self-gravity is capable of sustaining such lopsided configurations if and when stimulated by external perturbations. Here, we present results of N-body simulations which show unstable counter-rotating stellar clusters around super-massive black holes saturating into uniformly precessing lopsided nuclei. The double nucleus in our featured experiment decomposes naturally into a thick eccentric disk of apo-apse aligned stars which is embedded in a lighter triaxial cluster. The eccentric disk reproduces key features of Keplerian disk models of Andromeda's double nucleus; the triaxial cluster has a distinctive kinematic signature which is evident in HST observations of Andromeda's double nucleus, and has been difficult to reproduce with Keplerian disks alone. Our simulations demonstrate how the combination of eccentric disk and triaxial cluster arises naturally when a star cluster accreted over a pre-existing and counter-rotating disk of stars, drives disk and cluster into a mutually destabilizing dance. Such accretion events are inherent to standard galaxy formation scenarios. They are here shown to double stellar black hole nuclei as they feed them.

7 pages, 4 figures, Submitted to MNRAS

References in corpus (3)

• Lopsided Spiral Galaxies
• The Origin of the Young Stars in the Nucleus of M31
• Is there a black hole in NGC 4382?

Cited by in corpus (12)

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• A Slowly Precessing Disk in the Nucleus of M31 as the Feeding Mechanism for a Central Starburst
• Potential softening and eccentricity dynamics in razor-thin, nearly-Keplerian discs
• An order-disorder phase transition in black-hole star clusters
• The Black Hole Mass and the Stellar Ring in NGC 3706
• Secular Dynamics around a Supermassive Black Hole via Multipole Expansion
• Giant Planet Influence on the Collective Gravity of a Primordial Scattered Disk
• Apsidal Clustering following the Inclination Instability
• Growing a nuclear star cluster from star formation and cluster mergers: The JWST NIRSpec view of NGC 4654
• Secular Instabilities of Keplerian Stellar Discs