NH$_{3}$ Survey Observation of Massive Star-Forming Region W 43
| Autor: | Tetsuhiro Minamidani, Yukie Ohishi, Keita Hosaka, Asao Habe, Masayuki Y. Fujimoto, Yoshimasa Watanabe, Kazuhito Motogi, Kazuo Sorai, Hiroyuki Nishitani |
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| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Publications of the Astronomical Society of Japan. 64:30 |
| ISSN: | 2053-051X 0004-6264 |
| Popis: | We consider the properties of giant molecular cloud complexes in the star-forming region W 43 with a resolution of several pc scale, and discuss their relations to the evolutionary stages of massive star formation. We performed aN H 3 (J , K) = (1, 1), (2, 2), and (3, 3) inversion-line survey with the Hokkaido University 11-m telescope. Among 51 observed positions, selected based on integrated intensity maps of 13 CO (J = 1–0), these three emissions were detected from 21, 8, and 5 positions, respectively. The integrated intensity of the NH3 (J , K) = (1, 1) line was found to be proportional to the far-infrared luminosity, estimated from IRAS data. The rotation temperatures were deduced to be � 15–20 K at eight observed positions. In addition, the upper limits were estimated for 13 positions, which include the relatively low temperatures below 14 K at two positions with a relatively high fractions of NH3 for 13 CO and with a low far-infrared luminosity. We derived the ortho-to-para abundance ratio of NH3. From the population distribution between the ortho- and para-levels of NH3, we also derived temperatures of � 6–12 K, which may be interpreted as the temperatures when NH3 molecules were formed. We discuss the relevance of the present results of our observations to the massive star-formation process and the current status of the W 43 region while taking into account previous observations of other indicators of massive star formation. It is shown that the complexes contain several regions in different evolutionary stages, or with the distinct characteristics of star formation within a timescales shorter than the lifetime of massive stars. |
| Databáze: | OpenAIRE |
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