The Position, Motion, and Mass of Sgr A*

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.

arXiv comment7 pages, 4 figures

References in corpus (4)

• Closest Star Seen Orbiting the Supermassive Black Hole at the Centre of the Milky Way
• The Proper Motion of SgrA*: I. First VLBA Results
• Proper Motion of the Compact, Nonthermal Radio Source in the Galactic Center, Sagittarius a*
• Dynamics of a Massive Black Hole at the Center of a Dense Stellar System

Cited by in corpus (10)

• The Stellar Cusp Around the Supermassive Black Hole in the Galactic Center
• Ejection of hypervelocity stars by the (binary) black hole(s) in the Galactic center
• Stellar Processes Near the Massive Black Hole in the Galactic Center
• A size of ~1 AU for the radio source Sgr A* at the centre of the Milky Way
• The Milky Way's Supermassive Black Hole: How good a case is it? A Challenge for Astrophysics & Philosophy of Science
• Brownian Motion of Black Holes in Dense Nuclei
• A possible 3:2 orbital epicyclic resonance in QPOs frequencies of Sgr A*
• Observing the Galaxy's massive black hole with gravitational wave bursts
• Expectations for extreme-mass-ratio bursts from the Galactic Centre
• Numerical simulations of axisymmetric hydrodynamical Bondi-Hoyle accretion onto a compact object