A CO(J=2-1) line survey of the Galactic center

T. Sawada; T. Hasegawa; T. Handa; K. S. Usuda; J. I. Morino; R. Booth; L. Bronfman; A. Luna C.; M. Hayashi; L. Å Nyman; T. Oka; S. Sakamoto; M. Seta; P. Shaver; K. Sorai

doi:10.1016/S0273-1177(99)00253-7

A CO(J=2-1) line survey of the Galactic center

T. Sawada, T. Hasegawa, T. Handa, K. S. Usuda, J. I. Morino, R. Booth, L. Bronfman, A. Luna C., M. Hayashi, L. Å Nyman, T. Oka, S. Sakamoto, M. Seta, P. Shaver, K. Sorai

研究成果: Article › 査読

2 被引用数 (Scopus)

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We have observed the Galactic center in ¹² CO(J = 2-1) and ¹³ CO(J = 2-1) lines using the Tokyo-Onsala-ESO-Calán 60-cm telescope and compared the data with the ¹² CO(J = 1-0) Columbia survey (Bitran et al. 1997). The ¹² CO J = 2-1/J = 1-0 intensity ratio is very high (0.96) in the central 900 pc of the Galaxy, although it is about 0.6-0.7 for typical molecular clouds in the Galactic disk. The observed intensity ratios, ¹² CO J = 2-1/J = 1-0 and ¹³ CO/ ¹² CO (J = 2-1), indicate that even the ¹² CO line is not very optically thick: τ12 _CO(J=1-0) ∼ 1 or smaller in the Galactic center. This may be due to high temperature and large velocity dispersion. The large velocity dispersion is probably caused by large external pressure and tidal forces.

本文言語	English
ページ（範囲）	985-989
ページ数	5
ジャーナル	Advances in Space Research
巻	23
号	5-6
DOI	https://doi.org/10.1016/S0273-1177(99)00253-7
出版ステータス	Published - 1999
外部発表	はい

ASJC Scopus subject areas

航空宇宙工学
天文学と天体物理学
地球物理学
大気科学
宇宙惑星科学
地球惑星科学（全般）

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@article{79dd0f8fdad74251a42b4a4a3c5e3347,

title = "A CO(J=2-1) line survey of the Galactic center",

abstract = " We have observed the Galactic center in 12 CO(J = 2-1) and 13 CO(J = 2-1) lines using the Tokyo-Onsala-ESO-Cal{\'a}n 60-cm telescope and compared the data with the 12 CO(J = 1-0) Columbia survey (Bitran et al. 1997). The 12 CO J = 2-1/J = 1-0 intensity ratio is very high (0.96) in the central 900 pc of the Galaxy, although it is about 0.6-0.7 for typical molecular clouds in the Galactic disk. The observed intensity ratios, 12 CO J = 2-1/J = 1-0 and 13 CO/ 12 CO (J = 2-1), indicate that even the 12 CO line is not very optically thick: τ12 CO(J=1-0) ∼ 1 or smaller in the Galactic center. This may be due to high temperature and large velocity dispersion. The large velocity dispersion is probably caused by large external pressure and tidal forces.",

author = "T. Sawada and T. Hasegawa and T. Handa and Usuda, {K. S.} and Morino, {J. I.} and R. Booth and L. Bronfman and {Luna C.}, A. and M. Hayashi and Nyman, {L. {\AA}} and T. Oka and S. Sakamoto and M. Seta and P. Shaver and K. Sorai",

year = "1999",

doi = "10.1016/S0273-1177(99)00253-7",

language = "English",

volume = "23",

pages = "985--989",

journal = "Life sciences and space research",

issn = "0273-1177",

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number = "5-6",

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TY - JOUR

T1 - A CO(J=2-1) line survey of the Galactic center

AU - Sawada, T.

AU - Hasegawa, T.

AU - Handa, T.

AU - Usuda, K. S.

AU - Morino, J. I.

AU - Booth, R.

AU - Bronfman, L.

AU - Luna C., A.

AU - Hayashi, M.

AU - Nyman, L. Å

AU - Oka, T.

AU - Sakamoto, S.

AU - Seta, M.

AU - Shaver, P.

AU - Sorai, K.

PY - 1999

Y1 - 1999

N2 - We have observed the Galactic center in 12 CO(J = 2-1) and 13 CO(J = 2-1) lines using the Tokyo-Onsala-ESO-Calán 60-cm telescope and compared the data with the 12 CO(J = 1-0) Columbia survey (Bitran et al. 1997). The 12 CO J = 2-1/J = 1-0 intensity ratio is very high (0.96) in the central 900 pc of the Galaxy, although it is about 0.6-0.7 for typical molecular clouds in the Galactic disk. The observed intensity ratios, 12 CO J = 2-1/J = 1-0 and 13 CO/ 12 CO (J = 2-1), indicate that even the 12 CO line is not very optically thick: τ12 CO(J=1-0) ∼ 1 or smaller in the Galactic center. This may be due to high temperature and large velocity dispersion. The large velocity dispersion is probably caused by large external pressure and tidal forces.

AB - We have observed the Galactic center in 12 CO(J = 2-1) and 13 CO(J = 2-1) lines using the Tokyo-Onsala-ESO-Calán 60-cm telescope and compared the data with the 12 CO(J = 1-0) Columbia survey (Bitran et al. 1997). The 12 CO J = 2-1/J = 1-0 intensity ratio is very high (0.96) in the central 900 pc of the Galaxy, although it is about 0.6-0.7 for typical molecular clouds in the Galactic disk. The observed intensity ratios, 12 CO J = 2-1/J = 1-0 and 13 CO/ 12 CO (J = 2-1), indicate that even the 12 CO line is not very optically thick: τ12 CO(J=1-0) ∼ 1 or smaller in the Galactic center. This may be due to high temperature and large velocity dispersion. The large velocity dispersion is probably caused by large external pressure and tidal forces.

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U2 - 10.1016/S0273-1177(99)00253-7

DO - 10.1016/S0273-1177(99)00253-7

M3 - Article

AN - SCOPUS:0039134633

SN - 0273-1177

VL - 23

SP - 985

EP - 989

JO - Life sciences and space research

JF - Life sciences and space research

IS - 5-6

ER -

A CO(J=2-1) line survey of the Galactic center

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