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, Tomoharu Oka, S. Sakamoto, M. Seta, P. Shaver, K. Sorai

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We have observed the Galactic center in 12CO(J = 2-1) and 13CO(J = 2-1) lines using the Tokyo-Onsala-ESO-Calán 60-cm telescope and compared the data with the 12CO(J = 1-0) Columbia survey (Bitran et al. 1997). The 12CO 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, 12CO J = 2-1/J = 1-0 and 13CO/12CO (J = 2-1), indicate that even the 12CO line is not very optically thick: τ12CO(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.

Original languageEnglish
Pages (from-to)985-989
Number of pages5
JournalAdvances in Space Research
Volume23
Issue number5-6
Publication statusPublished - 1999
Externally publishedYes

Fingerprint

Columbia (Orbiter)
Galaxies
European Southern Observatory
molecular clouds
Telescopes
telescopes
galaxies
Temperature

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Sawada, T., Hasegawa, T., Handa, T., Usuda, K. S., Morino, J. I., Booth, R., ... Sorai, K. (1999). A CO(J=2-1) line survey of the Galactic center. Advances in Space Research, 23(5-6), 985-989.

A CO(J=2-1) line survey of the Galactic center. / Sawada, T.; Hasegawa, T.; Handa, T.; Usuda, K. S.; Morino, J. I.; Booth, R.; Bronfman, L.; Luna C., A.; Hayashi, M.; Nyman, L. Å; Oka, Tomoharu; Sakamoto, S.; Seta, M.; Shaver, P.; Sorai, K.

In: Advances in Space Research, Vol. 23, No. 5-6, 1999, p. 985-989.

Research output: Contribution to journalArticle

Sawada, T, Hasegawa, T, Handa, T, Usuda, KS, Morino, JI, Booth, R, Bronfman, L, Luna C., A, Hayashi, M, Nyman, LÅ, Oka, T, Sakamoto, S, Seta, M, Shaver, P & Sorai, K 1999, 'A CO(J=2-1) line survey of the Galactic center', Advances in Space Research, vol. 23, no. 5-6, pp. 985-989.
Sawada T, Hasegawa T, Handa T, Usuda KS, Morino JI, Booth R et al. A CO(J=2-1) line survey of the Galactic center. Advances in Space Research. 1999;23(5-6):985-989.
Sawada, T. ; Hasegawa, T. ; Handa, T. ; Usuda, K. S. ; Morino, J. I. ; Booth, R. ; Bronfman, L. ; Luna C., A. ; Hayashi, M. ; Nyman, L. Å ; Oka, Tomoharu ; Sakamoto, S. ; Seta, M. ; Shaver, P. ; Sorai, K. / A CO(J=2-1) line survey of the Galactic center. In: Advances in Space Research. 1999 ; Vol. 23, No. 5-6. pp. 985-989.
@article{79dd0f8fdad74251a42b4a4a3c5e3347,
title = "A CO(J=2-1) line survey of the Galactic center",
abstract = "We have observed the Galactic center in 12CO(J = 2-1) and 13CO(J = 2-1) lines using the Tokyo-Onsala-ESO-Cal{\'a}n 60-cm telescope and compared the data with the 12CO(J = 1-0) Columbia survey (Bitran et al. 1997). The 12CO 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, 12CO J = 2-1/J = 1-0 and 13CO/12CO (J = 2-1), indicate that even the 12CO line is not very optically thick: τ12CO(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 Tomoharu Oka and S. Sakamoto and M. Seta and P. Shaver and K. Sorai",
year = "1999",
language = "English",
volume = "23",
pages = "985--989",
journal = "Advances in Space Research",
issn = "0273-1177",
publisher = "Elsevier Limited",
number = "5-6",

}

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, Tomoharu

AU - Sakamoto, S.

AU - Seta, M.

AU - Shaver, P.

AU - Sorai, K.

PY - 1999

Y1 - 1999

N2 - We have observed the Galactic center in 12CO(J = 2-1) and 13CO(J = 2-1) lines using the Tokyo-Onsala-ESO-Calán 60-cm telescope and compared the data with the 12CO(J = 1-0) Columbia survey (Bitran et al. 1997). The 12CO 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, 12CO J = 2-1/J = 1-0 and 13CO/12CO (J = 2-1), indicate that even the 12CO line is not very optically thick: τ12CO(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 12CO(J = 2-1) and 13CO(J = 2-1) lines using the Tokyo-Onsala-ESO-Calán 60-cm telescope and compared the data with the 12CO(J = 1-0) Columbia survey (Bitran et al. 1997). The 12CO 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, 12CO J = 2-1/J = 1-0 and 13CO/12CO (J = 2-1), indicate that even the 12CO line is not very optically thick: τ12CO(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.

UR - http://www.scopus.com/inward/record.url?scp=0039134633&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0039134633&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0039134633

VL - 23

SP - 985

EP - 989

JO - Advances in Space Research

JF - Advances in Space Research

SN - 0273-1177

IS - 5-6

ER -