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TRIGONOMETRIC PARALLAXES OF HIGH MASS STAR FORMING REGIONS: THE STRUCTURE AND KINEMATICS OF THE MILKY WAY
Over 100 trigonometric parallaxes and proper motions for masers associated with young, high- mass stars have been measured with the Bar and Spiral Structure Legacy Survey, a Very Long Baseline ArrayExpand
The distance to the center of the Galaxy
For nearly a century astronomers have expended considerable effort to determine the size of the Milky Way. This effort is worthwhile because any change in the value of the distance from the Sun toExpand
TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. VI. GALACTIC STRUCTURE, FUNDAMENTAL PARAMETERS, AND NONCIRCULAR MOTIONS
We are using the Very Long Baseline Array and the Japanese VLBI Exploration of Radio Astronomy project to measure trigonometric parallaxes and proper motions of masers found in high-mass star-formingExpand
A 2.4% Determination of the Local Value of the Hubble Constant
We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant (H_0) from 3.3% to 2.4%. Improvements come from new,Expand
The Proper Motion of Sagittarius A*. II. The Mass of Sagittarius A*
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*Expand
A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way
TLDR
Ten years of high-resolution astrometric imaging allow us to trace two-thirds of the orbit of the star currently closest to the compact radio source (and massive black-hole candidate) Sagittarius A* and show that the star is on a bound, highly elliptical keplerian orbit around Sgr A*. Expand
The distance to the Orion Nebula
We have used the Very Long Baseline Array to measure the trigonometric parallax of several member stars of the Orion Nebula Cluster showing non-thermal radio emission. We have determined the distanceExpand
Parallaxes and proper motions of interstellar masers toward the Cygnus X star-forming complex. I. Membership of the Cygnus X region
Context. Whether the Cygnus X complex consists of one physically connected region of star formation or of multiple independent regions projected close together on the sky has been debated forExpand
The Distance to the Perseus Spiral Arm in the Milky Way
TLDR
The distance to the massive star–forming region W3OH in the Perseus spiral arm of the Milky Way is measured by triangulation, with Earth's orbit as one segment of a triangle, using the Very Long Baseline Array, resolving the long-standing problem that there is a discrepancy between different techniques used to determine distances. Expand
A Trigonometric Parallax of Sgr B2
We have measured the positions of H(2)O masers in Sgr B2, a massive star-forming region in the Galactic center, relative to an extragalactic radio source with the Very Long Baseline Array. TheExpand
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