Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2009-06-02
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
10 pages, 7 figures, 1 table, accepted for publication in MNRAS
Scientific paper
Observations of the Galactic Centre show evidence of one or two disc-like structures of very young stars orbiting the central super-massive black hole within a distance of a few 0.1 pc. A number of analyses have been carried out to investigate the dynamical behaviour and consequences of these discs, including disc thickness and eccentricity growth as well as mutual interaction and warping. However, most of these studies have neglected the influence of the stellar cusp surrounding the black hole, which is believed to be 1-2 orders of magnitude more massive than the disc(s). By means of N-body integrations using our bhint code, we study the impact of stellar cusps of different compositions. We find that although the presence of a cusp does have an important effect on the evolution of an otherwise isolated flat disc, its influence on the evolution of disc thickness and warping is rather mild in a two-disc configuration. However, we show that the creation of highly eccentric orbits strongly depends on the graininess of the cusp (i.e. the mean and maximum stellar masses): While Chang (2009) recently found that full cycles of Kozai resonance are prevented by the presence of an analytic cusp, we show that relaxation processes play an important role in such highly dense regions and support short-term resonances. We thus find that young disc stars on initially circular orbits can achieve high eccentricities by resonant effects also in the presence of a cusp of stellar remnants, yielding a mechanism to create S-stars and hyper-velocity stars. Furthermore, we discuss the underlying initial mass function (IMF) of the young stellar discs and find no definite evidence for a non-canonical IMF.
Baumgardt Holger
Kroupa Pavel
Löckmann Ulf
No associations
LandOfFree
Influence of a stellar cusp on the dynamics of young stellar discs and the origin of the S-stars in the Galactic Centre does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Influence of a stellar cusp on the dynamics of young stellar discs and the origin of the S-stars in the Galactic Centre, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Influence of a stellar cusp on the dynamics of young stellar discs and the origin of the S-stars in the Galactic Centre will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-193142