Multi-Epoch VERA Observations of H2O Masers in OH 43.8−0.1
| Autor: | Hiroshi Imai, Chung Sik Oh, Satoshi Sakai, Yukitoshi Kan-ya, Tomoaki Oyama, Yoon Kyung Choi, José K. Ishitsuka, Kouichirou Nakashima, Seiji Manabe, Ryuichi Kamohara, Toshihiro Omodaka, Noriyuki Kawaguchi, Yoshiaki Tamura, Tomoya Hirota, Takahiro Fujii, Takeshi Miyaji, Osamu Kameya, Mareki Honma, Masachika Kijima, Seisuke Kuji, Katsuhisa Sato, K. Yamashita, Tetsuo Sasao, Takaaki Jike, Tomoharu Kurayama, Akiharu Nakagawa, Takeshi Bushimata, Kenzaburo Iwadate, K. Horiai, Hiroshi Suda, Noritomo Inomata, Kasumi Sora, Hideyuki Kobayashi, Katsunori M. Shibata, R. Shimizu, Maria Rioja |
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| Rok vydání: | 2005 |
| Předmět: |
Physics
Astronomy Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Astrometry Radius Rotation law.invention Radial velocity Space and Planetary Science law Very-long-baseline interferometry Astrophysics::Solar and Stellar Astrophysics OH/IR star Maser Astrophysics::Galaxy Astrophysics Galaxy rotation curve |
| Zdroj: | Publications of the Astronomical Society of Japan. 57:595-603 |
| ISSN: | 2053-051X 0004-6264 |
| DOI: | 10.1093/pasj/57.4.595 |
| Popis: | We report on multi-epoch observations of H2O maser emission in the star-forming region OH 43.8−0.1, carried out with VLBI Exploration of Radio Astrometry. The large-scale maser distributions obtained by single-beam VLBI mapping reveal new maser spots scattered over the area of 0. 7 ×1. 0, in addition to a ‘shell-like’ structure with a scale of 0. 3 ×0. �� 5, which was mapped previously. Proper motions were also obtained for 43 spots based on 5-epoch monitoring with a time span of 281 days. The distributions of the proper motions show a systematic outflow in the north–south direction with an expansion velocity of ∼ 8kms −1 . The overall distributions of the maser spots as well as the proper motions are better represented by a bipolar flow plus a central maser cluster with a complex structure, rather than a shell with uniform expansion, such as those found in Cep A R5 and W75N VLA2. The distance to OH 43.8−0.1 was also estimated based on the statistical parallax, yielding D =2 .8 ±0.5kpc. This distance is consistent with a near kinematic distance, and rules out a far kinematic distance (∼ 9kpc). Also, the radial velocity of the OH 43.8−0.1 combined with the distance provides a constraint on the flatness of the galactic rotation curve, indicating that there is no systematic difference in the rotation speeds at the Sun and at the position of OH 43.8−0.1, which is located at a galacto-centric radius of ∼ 6.3kpc. |
| Databáze: | OpenAIRE |
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