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- Title
Astrometry of Galactic star-forming regions G48.99-0.30 and G49.19-0.34 with VERA:Astrometric accuracy verification of VERA.
- Authors
Takumi NAGAYAMA; Hideyuki KOBAYASHI; Toshihiro OMODAKA; Yasuhiro MURATA; Ross A. BURNS; Mareki HONMA; Tomoharu KURAYAMA; Akiharu NAKAGAWA; Tomoaki OYAMA; Yoshiaki TAMURA; Katsuhisa SATO
- Abstract
We conducted astrometry of H2O masers in Galactic star-forming regions G48.99-0.30 and G49.19-0.34 with VLBI Exploration of Radio Astrometry (VERA). The observational results yield the parallaxes of G48.99-0.30 and G49.19-0.34 to be 0.178±0.017 mas (5.62+0.59-0.49 kpc) and 0.211±0.016 mas (4.74+0.39-0.33 kpc), respectively. We discuss in detail the sources of astrometric errors based on the observations of the two sources. The positional systemic errors in RA and Dec of (23, 31)μ as for G49.19-0.34 are dominated by a tropospheric contribution from the Earth's atmosphere. Those of (23, 53)μas for G48.99-0.30 are attributed to a tropospheric contribution and a maser structure effect. The formal positional error from thermal noise is significantly smaller than these systemic positional errors. VERA phase-referencing observations could achieve a positional accuracy of a few tens of μas in both RA and Dec directions for point-like and bright sources at high elevation.
- Subjects
ASTROMETRY; PARALLAX; ASTROPHYSICS; TROPOSPHERE; INTERFEROMETRY
- Publication
Publications of the Astronomical Society of Japan, 2015, Vol 67, Issue 4, p1
- ISSN
0004-6264
- Publication type
Article
- DOI
10.1093/pasj/psu129