A Trigonometric Parallax of Sgr B2
M. J. Reid(1), K. M. Menten(2), X. W. Zheng(3), A. Brunthaler(2), Y. Xu(4)
(1) Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
(2) Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
(3) Department of Astronomy, Nanjing University Nanjing 210093, China
(4) Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China
Paper: submitted to ApJ
Abstract:
We have measured the positions of H2O masers in Sgr B, a massive star
forming region in the Galactic center, relative to an extragalactic
radio source with the Very Long Baseline Array. The positions measured
at 12 epochs over a time span of one year yield the trigonometric
parallax of Sgr B and hence a distance to the Galactic center of
Ro=7.9+0.8_-0.7 kpc. The proper motion of Sgr B relative to
Sgr A suggests that Sgr B is 0.13 kpc nearer than the
Galactic center, assuming a low-eccentricity Galactic orbit.
Preprints available from the authors at reid@cfa.harvard.edu
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