Astrometry of Galactic Star Forming Region Sharpless 269 with VERA : Parallax Measurements and Constraint on Outer Rotation Curve
| Autor: | Yoshiaki Tamura, Ryuichi Kamohara, Masachika Kijima, Tomoharu Kurayama, Katsuhisa Sato, Hiroshi Suda, Kenzaburo Iwadate, Akiharu Nakagawa, Chung Sik Oh, Yukitoshi Kan-ya, Kazuyoshi Yamashita, Takeshi Miyaji, Takeshi Bushimata, Katsunori M. Shibata, Seiji Manabe, Hiroshi Imai, Motonobu Shintani, Toshihiro Omodaka, Tomoya Hirota, Osamu Kameya, Tomoaki Oyama, Yoon Kyung Choi, Noriyuki Kawaguchi, Hideyuki Kobayashi, Miyuki Tsushima, Takaaki Jike, Seisuke Kuji, Takumi Nagayama, Tetsuo Sasao, Mareki Honma, Satoshi Sakai |
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| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Physics
Dark matter Astrophysics (astro-ph) FOS: Physical sciences Astronomy and Astrophysics Astrometry Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Rotation Galaxy law.invention Space and Planetary Science law Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Maser Flatness (cosmology) Parallax Galaxy rotation curve Astrophysics::Galaxy Astrophysics |
| Popis: | We have performed high-precision astrometry of H2O maser sources in Galactic star forming region Sharpless 269 (S269) with VERA. We have successfully detected a trigonometric parallax of 189+/-8 micro-arcsec, corresponding to the source distance of 5.28 +0.24/-0.22 kpc. This is the smallest parallax ever measured, and the first one detected beyond 5 kpc. The source distance as well as proper motions are used to constrain the outer rotation curve of the Galaxy, demonstrating that the difference of rotation velocities at the Sun and at S269 (which is 13.1 kpc away from the Galaxy's center) is less than 3%. This gives the strongest constraint on the flatness of the outer rotation curve and provides a direct confirmation on the existence of large amount of dark matter in the Galaxy's outer disk. 7 pages and 4 figures, Accepted by PASJ (Vol. 59, No. 5, October 25, 2007 issue) |
| Databáze: | OpenAIRE |
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