Year: 2007
Type: article
Abstract: We consider the dynamical evolution of a disk of stars orbiting a central black hole. In particular, we focus on the effect of the stellar mass function on the evolution of the disk, using both analytic arguments and numerical simulations. We apply our model to the ring of massive stars at ≃0.1 pc from the Galactic center, assuming that the stars formed in a cold, circular disk, and find that our model requires the presence of a significant population of massive (>100 M ☉ ) stars in order to explain the observed eccentricities of 0.2-0.3. Moreover, in order to limit the damping of the heavier stars' eccentricities, we also require fewer low-mass stars than expected from a Salpeter mass function, giving strong evidence for a significantly "top-heavy" mass function in the rings of stars seen near to the Galactic center. We also note that the maximum possible eccentricities attainable from circular initial conditions at ages of <10 Myr are around 0.4-0.5, and we suggest that any rings of stars found with higher eccentricities were probably not formed from circular disks.
Source: The Astrophysical Journal
DOI: 10.1086/509709
Authors: Richard D. Alexander, Mitchell C. Begelman, Philip J. Armitage
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1974338791