Related papers: An Updated Reference Frame for the Galactic Inner …

We report Very Long Baseline Array (VLBA) observations of 43 GHz v=1, J=1-0 SiO masers in the circumstellar envelope of the M-type semi-regular variable star VX Sgr at 3 epochs during 1999 April-May. These high-resolution VLBA images reveal…

A moderately deep survey of stellar maser sources toward the Galactic center has been made in the SiO J=1-0 v=1 and v=2 transitions (~ 43 GHz) with the Nobeyama 45-m telescope of a beam size of about 40". At the Galactic center (Sgr A*), 7…

We report on the submillimeter properties of Sagittarius A* derived from observations with the Submillimeter Array and its polarimeter. We find that the spectrum of Sgr A* between 230 and 690 GHz is slightly decreasing when measured…

We have studied the kinematics of Galactic masers and radio stars with measured VLBI trigonometric parallaxes and proper motions. We have considered masers with relative trigonometric parallax errors less than 10\% and determined the…

We have conducted VLBA phase-referencing monitoring of H2O masers around the red supergiant, S Persei, for six years. We have fitted maser motions to a simple expanding-shell model with a common annual parallax and stellar proper motion,…

Some galactic theories of spiral arms predict an offset between different tracers of star formation. Our goal here is to find such an offset between the observed location of radio masers and the location of the arms, using a recent 4-arm…

Asymptotic Giant Branch (AGB) stars are good tracers of the Galactic structure. They are bright in the infrared and can therefore be detected even in the most obscured regions of the Galaxy. Maser emission from their circumstellar envelopes…

As part of a reanalysis of galactic Asymptotic Giant Branch (AGB) stars at infrared (IR) wavelengths, we discuss a sample (357) of carbon stars for which mass loss rates, near-IR photometry and distance estimates exist. For 252 sources we…

We combine Gaia DR1, PS1, SDSS and 2MASS astrometry to measure proper motions for 350 million sources across three-fourths of the sky down to a magnitude of $m_r\sim20$\,. Using positions of galaxies from PS1, we build a common reference…

We present 86 GHz (v = 1, J = 2 -1) SiO maser line observations with the IRAM 30-m telescope of a sample of 441 late-type stars in the Inner Galaxy (-4 degr < l < +30 degr). These stars were selected on basis of their infrared magnitudes…

We present details of the second part of the Southern Infrared Proper Motion Survey (SIPS). Here accurate relative astrometry allows us to reduce the minimum proper motion to 0.1 arcseconds per year. This yields 6904 objects with proper…

We report new precision measurements of the properties of our Galaxy's supermassive black hole. Based on astrometric (1995-2007) and radial velocity (2000-2007) measurements from the W. M. Keck 10-meter telescopes, a fully unconstrained…

We report measurements with the Very Long Baseline Array of the proper motion of Sgr A* relative to two extragalactic radio sources spanning 18 years. The apparent motion of Sgr A* is -6.411 +/- 0.008 mas/yr along the Galactic plane and…

Recent broad-band 34 and 44 GHz radio continuum observations of the Galactic center have revealed 41 massive stars identified with near-IR counterparts, as well as 44 proplyd candidates within 30" of Sgr A*. Radio observations obtained in…

The high accuracy of modern space astrometry requires the use of General Relativity to model the propagation of stellar light through the gravitational field encountered from a source to a given observer inside the Solar System. In this…

This work presents the results from extending the long-term monitoring program of stellar motions within the Galactic Center to include stars with separations of 2 - 7 arcseconds from the compact radio source, Sgr A*. In comparison to the…

We present the Australia Telescope Compact Array (ATCA) observations of the SiO masers in the Galactic center in transitions of v=1, J=2--1 at 86 GHz and v=1, J=1--0 at 43 GHz. Two 86-GHz SiO masers were detected within the central parsec,…

We present the results of observations of cold IRAS sources in the Galactic disk area, -10 < l < 100 and |b|<5, in the SiO J=1-0, v=1 and 2 maser lines. SiO masers were detected in 51 out of 143 observed sources; 45 were new detections in…

We present the very long baseline interferometry H2O maser monitoring observations of the red supergiant, PZ Cas, at 12 epochs from 2006 April to 2008 May. We fitted maser motions to a simple model composed of a common annual parallax and…

We present a detailed analysis of the kinematics of SiO maser stars around the center of the Milky Way, Sagittarius A* (Sgr A*). We used the archive data in the SiO v=1, J=2-1 emission line obtained by the Atacama Large…