Clockwise Stellar Disk and the Dark Mass in the Galactic Center
Andrei M. Beloborodov1,2, Yuri Levin3, Frank Eisenhauer4, Reinhard Genzel4,5, Thibaut Paumard4, Stefan Gillessen4, Thomas Ott4
(1) Physics Department and Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street New York, NY 10027
(2) Astro-Space Center of Lebedev Physical Institute, Profsojuznaja 84/32, Moscow 117810, Russia
(3) Leiden Observatory, PO Box 9513, NL-2300 RA, Leiden, The Netherlands
(4) Max-Planck Institut für extraterrestrische Physik (MPE), Garching, Germany
(5) Department of Physics, University of California, Berkeley, CA 94720
Paper: ApJ, submitted
Abstract:
Two disks of young stars have recently been discovered in the
Galactic Center. The disks are rotating in the gravitational field
of the central black hole at radii r 0.1-0.3 pc and thus open
a new opportunity to measure the central mass. We find that the
observed motion of stars in the clockwise disk implies
M=(4.3+/- 0.5)* 106M_o for the fiducial distance to the
Galactic Center R0=8 kpc and derive the scaling of M with R0.
As a tool for our estimate we use orbital roulette, a recently
developed method. The method reconstructs the three-dimensional orbits
of the disk stars and checks the randomness of their orbital phases.
The clockwise-disk stars are found to have modest orbital eccentricities.
Preprints available from the authors at amb@phys.columbia.edu
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