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The Position, Motion, and Mass of Sgr A*
Author(s) -
Reid Mark J.,
Menten Karl M.,
Genzel Reinhard,
Ott Thomas,
Schödel Rainer,
Brunthaler Andreas
Publication year - 2003
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200385084
Subject(s) - physics , proper motion , astrophysics , astronomy , infrared , orbital motion , galactic plane , position (finance) , stars , finance , quantum mechanics , angular momentum , economics
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 motion of 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 −1 . Finally, combining stellar orbital information with an upper limit of 8 km s −1 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 × 10 5 M ⊙ .