The pattern speed of the nuclear disk of M31 using a variant of the Tremaine-Weinberg method

Abstract

The twin peaks in the nucleus of M31 have been interpreted by Tremaine as a thick, eccentric, disk of stars orbiting a massive dark object; the required alignment of the apoapsides of the stellar orbits could be maintained by self-gravity, and the whole structure might be a discrete, nonlinear eigenmode. The pattern speed of this mode could, in principle, be determined by the Tremaine-Weinberg (TW) method, which requires measurements of the surface brightness, and radial velocity along a strip parallel to the line of nodes. However, spectroscopic observations along the line of nodes are not available. We propose a variant of the TW method, which exploits a basic feature of the eccentric disk model, to extract estimates of the pattern speed from {\it Hubble Space Telescope} spectroscopic data, taken along the line joining the two peaks. Within limitations imposed by the data, we estimate that the pattern rotates in a prograde manner and, for an assumed disk inclination of $77^{\circ }$, the pattern speed $|{\Omega }_p|<30\mathrm{km}{\mathrm{s}}^{-1}\mathrm{p}{\mathrm{c}}^{-1}$, or period more than $200,000$ years.

5 pages, 2 figures, uses AASTeX502 Accepted for publication in Astrophysical Journal Letters

References in corpus (4)

• M32+/-1
• Stellar Dynamics around Black Holes in Galactic Nuclei
• Stellar Kinematics of the Double Nucleus of M31
• On the Nuclear Rotation Curve of M31

Cited by in corpus (11)

• The Nuclear Stellar Disk in Andromeda: A Fossil from the Era of Black Hole Growth
• The M 31 double nucleus probed with OASIS and HST. A natural m=1 mode?
• The Pattern Speeds of M51, M83 and NGC 6946 Using CO and the Tremaine-Weinberg Method
• Eccentric-disk models for the nucleus of M31
• Pattern Speeds of BIMA-SONG Galaxies with Molecule-Dominated ISMs Using the Tremaine-Weinberg Method
• The Origin of the Young Stars in the Nucleus of M31
• Dynamical Modeling of the Stellar Nucleus of M31
• Eccentric Nuclear Disks with Self Gravity: Predictions for the Double Nucleus of M31
• Self-Gravitating Eccentric Disk Models for the Double Nucleus of M31
• The Effect of General Relativistic Precession on Tidal Disruption Events from Eccentric Nuclear Disks
• A Slowly Precessing Disk in the Nucleus of M31 as the Feeding Mechanism for a Central Starburst