Trigonometric parallax and proper motion of Sagittarius A* measured by VERA using the new broad-band back-end system OCTAVE-DAS

We successfully measured the trigonometric parallax of Sagittarius A* (Sgr A*) to be 117 +/- 17 micro-arcseconds (mu as) using the VLBI Exploration of Radio Astrometry (VERA) with the newly developed broad-band signal-processing system named "OCTAVE-DAS." The measured parallax corresponds to a Galactocentric distance at the Sun of R-0=8.5(-1.1)(+1.5)kpc. By combining the astrometric results with VERA and the Very Long Baseline Array (VLBA) over a monitoring period of 25 yr, the proper motion of Sgr A* is obtained to be (mu(alpha), mu(delta)) = (-3.133 +/- 0.003, -5.575 +/- 0.005) mas yr(-1) in equatorial coordinates, corresponding to (mu(l), mu(b)) = (-6.391 +/- 0.005, -0.230 +/- 0.004) mas yr(-1) in Galactic coordinates. This gives an angular orbital velocity of the Sun of Omega(circle dot) = 30.30 +/- 0.02 km s(-1) kpc(-1). We find upper limits to the core wander, Delta theta < 0.20 mas (1.6 au), peculiar motion, Delta mu < 0.10 mas yr(-1) (3.7 km s(-1)), and acceleration, a < 2.6 mu asyr(-2) (0.10 km s(-1) yr(-1)) for Sgr A*. Thus, we obtained upper mass limits of approximate to 3x10(4)M(circle dot) and approximate to 3x10(3)M(circle dot) for the supposed intermediate-mass black holes at 0.1 and 0.01 pc from the Galactic center, respectively.