Astronomy and Astrophysics – Astrophysics
Scientific paper
2000-01-25
Mon.Not.Roy.Astron.Soc. 317 (2000) 348
Astronomy and Astrophysics
Astrophysics
35 pages, 17 figures, submitted to M.N.R.A.S
Scientific paper
10.1046/j.1365-8711.2000.03582.x
We report a new analysis of stellar dynamics in the Galactic centre, based on improved sky and LOS velocities for >100 stars within a few arcsec of SgrA*. Overall the motions do not deviate strongly from isotropy. For 32 stars with all 3 components determined the absolute, LOS and sky velocities agree well, as for a spherical cluster. The projected radial and tangential motions of all 104 pm stars are also consistent with overall isotropy. However, the projected velocities of the young, early type stars have a strong radial dependence. Most of the bright HeI stars 1-10" from SgrA* are on tangential orbits. This anisotropy of the HeI stars and most of the brighter IRS16 complex members is largely caused by a CW and counter-rotating, coherent rotation pattern. The overall rotation of the young star cluster probably is a remnant of the angular momentum in the cloud these stars formed from. The fainter, fast stars within \~1" of SgrA* appear to be largely moving on radial or very elliptical orbits. We have not detected nonlinear motion for any of them. Most of the SgrA* cluster members also are on CW orbits. Spectroscopy shows them to be early type stars. We propose that the SgrA* cluster stars are those members of the early type cluster with small angular momentum which can plunge to the vicinity of SgrA*. Our anisotropy-independent estimate of the Sun-GC distance is 7.8-8.2 kpc (+/- 0.9 kpc). We include velocity anisotropy in estimating the central mass distribution. We confirm previous conclusions that a compact central mass concentration is present and dominates the potential from 0.01-1 pc. The central mass ranges from 2.6-3.3E6 M_sun. (abridged)
Eckart Andreas
Genzel Reinhard
Gerhard Ortwin E.
Ott Th.
Pichon Christophe
No associations
LandOfFree
Stellar Dynamics in the Galactic centre: Proper Motions and Anisotropy 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 Stellar Dynamics in the Galactic centre: Proper Motions and Anisotropy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stellar Dynamics in the Galactic centre: Proper Motions and Anisotropy will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-308496