The Proper Motion of Sagittarius A*. II. The Mass of Sagittarius A*

@article{Reid2004ThePM,
  title={The Proper Motion of Sagittarius A*. II. The Mass of Sagittarius A*},
  author={Mark J. Reid and Andreas Brunthaler},
  journal={The Astrophysical Journal},
  year={2004},
  volume={616},
  pages={872 - 884}
}
We report measurements with the Very Long Baseline Array (VLBA) of the position of Sgr A* with respect to two extragalactic radio sources over a period of 8 yr. The apparent proper motion of Sgr A* relative to J1745-283 is 6.379 ± 0.024 mas yr-1 along a position angle of 209.°60 ± 0.°18, almost entirely in the plane of the Galaxy. The effects of the orbit of the Sun around the Galactic center can account for this motion, and the residual proper motion of Sgr A* perpendicular to the plane of the… 

Figures and Tables from this paper

THE PROPER MOTION OF THE GALACTIC CENTER PULSAR RELATIVE TO SAGITTARIUS A*
We measure the proper motion of the pulsar PSR J1745-2900 relative to the Galactic center massive black hole, Sgr A*, using the Very Long Baseline Array (VLBA). The pulsar has a transverse velocity
A RADIO TRANSIENT 0.1 PARSECS FROM SAGITTARIUS A
We report the discovery of a transient radio source 2.″7 (0.1 pc projected distance) south of the Galactic center massive black hole, Sgr A*. The source flared with a peak of at least 80 mJy in 2004
The Intrinsic Size of Sagittarius A* from 0.35 to 6 cm
We present new high-resolution observations of Sagittarius A* at wavelengths of 17.4-23.8 cm with the Very Large Array in the A configuration with the Pie Town Very Long Baseline Array (VLBA)
Probing Dynamical Activity of Sgr A* Using VLBI Closure Quantities
Sagittaruis A* is the name given to the compact radio source at the center of the Milky Way. In 1994 Narayan et al. noted that the source exhibited relatively low luminosity for the large amount of
TRIGONOMETRIC PARALLAX OF W51 MAIN/SOUTH
We report measurement of the trigonometric parallax of W51 Main/South using the Very Long Baseline Array. We measure a value of 0.185 ± 0.010 mas corresponding to a distance of 5.41+0.31−0.28 kpc.
Understanding the Radio Variability of Sagittarius A*
We determine the characteristics of the 7 mm to 20 cm wavelength radio variability in Sgr A* on timescales from days to three decades. The amplitude of the intensity modulation is between 30% and 39%
Constraining the Solar Galactic Reflex Velocity using Gaia Observations of the Sagittarius Stream
Because of its particular orientation around the Galaxy—i.e., in a plane nearly perpendicular to the Galactic plane and containing both the Sun and Galactic center—the Sagittarius (Sgr) stream
The uncertainty in Galactic parameters
We reanalyse the measurements of parallax, proper motion and line-of-sight velocity for 18 masers in high-mass star-forming regions presented by Reid et al. We use a likelihood analysis to
On the Formation of Compact Stellar Disks around Sagittarius A
The recent identification of one or two subparsec disks of young, massive stars orbiting the ~4 × 106 M☉ black hole Sgr A* has prompted an in situ scenario for star formation in disks of gas formed
Microarcsecond astrometry in the Local Group
Abstract Measuring the proper motions and geometric distances of galaxies within the Local Group is very important for our understanding of its history, present state and future. Currently, proper
...
...

References

SHOWING 1-10 OF 45 REFERENCES
The Proper Motion of Sagittarius A*. I. First VLBA Results
We observed Sgr A* and two extragalactic radio sources nearby in angle with the VLBA over a period of 2 yr and measured relative positions with an accuracy approaching 0.1 mas. The apparent proper
Nonacceleration of Sagittarius A*: Implications for Galactic Structure
We estimate that observations by Backer and collaborators over the past two decades constrain the time derivative of the proper motion of Sgr A* to be less than 0.14 mas yr-2. Using this result and a
The Position of Sagittarius A*. II. Accurate Positions and Proper Motions of Stellar SiO Masers near the Galactic Center
In 1979, Menten and coworkers accurately determined the position of Sgr A* on an infrared image by aligning the infrared image with positions measured for SiO masers, associated with infrared-bright
The Position of Sagittarius A*: Accurate Alignment of the Radio and Infrared Reference Frames at the Galactic Center
We present a novel approach to the long-standing problem of locating the position of the compact nonthermal radio source Sgr A* on infrared images of the Galactic center region. Using the Very Large
Possible Fluctuation of the Position of Sagittarius A* Relative to Extragalactic Radio Sources
When we measure the position of an extragalactic radio source through the Galaxy, apparent position wander will be induced because of the gravitational deflection by intervening stars in the Galaxy.
Proper Motion of the Compact, Nonthermal Radio Source in the Galactic Center, Sagittarius A*
Proper motions and radial velocities of luminous infrared stars in the Galactic center have provided strong evidence for a dark mass of 2.5 × 106 M☉ in the central 0.05 pc of the Galaxy. The leading
Structure of Sagittarius A* at 86 GHz using VLBI Closure Quantities
At radio wavelengths, images of the compact radio source Sagittarius A* (Sgr A*) in the Galactic center are scatter broadened with a λ2 dependence due to an intervening ionized medium. We present
High-Frequency Measurements of the Spectrum of Sagittarius A*
We report near-simultaneous interferometric measurements of the spectrum of Sagittarius A* over the 5-354 GHz range and single-dish observations that have yielded the first detection of Sgr A* at 850
Local stellar kinematics from Hipparcos data
TLDR
From the parallaxes and proper motions of a kinematically unbiased subsample of the Hipparcos Catalogue, it is re-determined as a function of colour the kinematics of main-sequence stars that spiral arms are responsible for the non-axisymmetry and that R0/Rd ≃ 3 to 3, where Rd is the scalelength of the disc.
The Stellar Cusp around the Supermassive Black Hole in the Galactic Center
We analyze deep near-IR adaptive optics imaging (taken with NAOS/CONICA on the Very Large Telescope at the European Southern Observatory, Chile), as well as new proper-motion data of the nuclear star
...
...