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The Position, Motion, and Mass of Sgr A*

M. J. Reid·K. M. Menten·R. Genzel·T. Ott·R. Schoedel·A. Eckart·A. Brunthaler
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Abstract

We report progress on measuring the position of Sgr A* on infrared images, placing limits on the motion of the central star cluster relative to Sgr A*, and measuring the proper motionof Sgr A* itself. The position of Sgr A* has been determined to within 10 mas on infrared images. To this accuracy, the gravitational source (sensed by stellar orbits) and the radiative source (Sgr A*) are coincident. Proper motions of four stars measured both in the infrared and radio indicate that the central star cluster moves with Sgr A* to within 70 km/s. Finally, combining stellar orbital information with an upper limit of 8 km/s for the intrinsic proper motion of Sgr A* (perpendicular to the Galactic plane), we place a lower limit on the mass of Sgr A* of 4 x 10^5 Msun.

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M. J. Reid, K. M. Menten, R. Genzel, T. Ott, R. Schoedel, A. Eckart, A. Brunthaler. 2003-04-04. The Position, Motion, and Mass of Sgr A*. https://doi.org/10.1002/asna.200385084

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