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| Paper: |
The Proper Motion of Sgr A* With Upgrade-VERA |
| Volume: |
528, New Horizons in Galactic Center Astronomy and Beyond |
| Page: |
115 |
| Authors: |
Oyama, T.; Nagayama, T.; Sakai, D.; Yamauchi, A. |
| Abstract: |
We measured the proper motion of Sgr A* relative to the background source J1745–2820 using VERA and the newly developed wide-band digital acquisition system of 12 Gbps providing the total band width of 3 GHz. The proper motion of Sgr A* was measured to be (μlcos b,μb) =(–6.307±0.025, –0.214±0.017) mas yr-1 in Galactic longitude and latitude directions. The sum of the angular velocity of Galactic rotation at LSR and the solar motion in the Galactic rotation direction is directly obtained to be Ω☉ = Ω0+V☉/R0 =29.90 ±0.12 km s-1 kpc-1 from the proper motion in Galactic longitude direction. By the VLBI astrometric monitoring observations over a period of 20 years, the peculiar motion and the acceleration of Sgr A* could be strongly limited to be ≤ 0.1 mas yr-1 (4 km s-1 at the distance of 8 kpc) and ≤ 0.004 mas yr–2 (0.2 km s-1 yr-1), respectively. |
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