TY - JOUR
T1 - High-resolution CO images of the Galactic central molecular zone
AU - Tokuyama, Sekito
AU - Oka, Tomoharu
AU - Takekawa, Shunya
AU - Iwata, Yuhei
AU - Tsujimoto, Shiho
AU - Yamada, Masaya
AU - Furusawa, Maiko
AU - Nomura, Mariko
N1 - Funding Information:
The James Clerk Maxwell Telescope is operated by the East Asian Observatory on behalf of The National Astronomical Observatory of Japan, the Academia Sinica Institute of Astronomy and Astrophysics, the Korea Astronomy and Space Science Institute, the National Astronomical Observatories of China, and the Chinese Academy of Sciences (Grant No. XDB09000000), with additional funding support from the Science and Technology Facilities Council of the United Kingdom and participating universities in the United Kingdom and Canada.
Funding Information:
The James Clerk Maxwell Telescope is operated by the East Asian Observatory on behalf of The National Astronomical Observatory of Japan, the Academia Sinica Institute of Astronomy and Astrophysics, the Korea Astronomy and Space Science Institute, the National Astronomical Observatories of China, and the Chinese Academy of Sciences (Grant No. XDB09000000), with additional funding support from the Science and Technology Facilities Council of the United Kingdom and participating universities in the United Kingdom and Canada. We are grateful to the Nobeyama Radio Observatory staff and all the members of the James Clerk Maxwell Telescope team for operation of the telescope. T.O. acknowledges support from Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research (B) No. 15H03643. S.T. acknowledges support from JSPS Grant-in-Aid for Research Fellows No. 15J04405
Funding Information:
We are grateful to the Nobeyama Radio Observatory staff and all the members of the James Clerk Maxwell Telescope team for operation of the telescope. T.O. acknowledges support from Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research (B) No. 15H03643. S.T. acknowledges support from JSPS Grant-in-Aid for Research Fellows No. 15J04405.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - We performed Nyquist-sampled mapping observations of the central molecular zone of our Galaxy in the J = 1-0 lines of CO, 13CO, and C18O using the 45 m telescope at the Nobeyama Radio Observatory. The newly obtained data sets were an improvement by a factor of four in spatial resolution of the CO data previously obtained with the same telescope 22 years ago, providing the highest angular resolution CO atlas of this special area of the Galaxy. The data cover the area: -0${^{\circ}_{.}}$8 ≤ l ≤ +1${^{\circ}_{.}}$4 and -0${^{\circ}_{.}}$35 ≤ b ≤ +0${^{\circ}_{.}}$35 with a 15″ beamwidth. Total intensity ratios for CO J = 3-2/J = 1-0, 13CO/CO J = 1-0 and C18O/13CO J = 1-0, are 0.70 ± 0.06, 0.12 ± 0.01, and 0.14 ± 0.01, respectively. The high-resolution CO images show the fine structure of the molecular gas and enable us to identify a number of compact clouds with broad velocity widths, i.e., high-velocity compact clouds. We conducted a detailed comparison of our CO J = 1-0 data with the CO J = 3-2 data obtained with the James Clerk Maxwell Telescope to derive the distribution and kinematics of the highly excited gas. Three, out of four, of the previously identified high CO J = 3-2/J = 1-0 ratio areas at l = +1${^{\circ}_{.}}$3, 0${^{\circ}_{.}}$0, and -0${^{\circ}_{.}}$4 were confirmed with a higher spatial resolution. In addition to these, we identified several very compact, high CO J = 3-2/J = 1-0 spots with broad velocity widths for the first time. These are candidates for accelerated gas in the vicinity of invisible, point-like massive objects.
AB - We performed Nyquist-sampled mapping observations of the central molecular zone of our Galaxy in the J = 1-0 lines of CO, 13CO, and C18O using the 45 m telescope at the Nobeyama Radio Observatory. The newly obtained data sets were an improvement by a factor of four in spatial resolution of the CO data previously obtained with the same telescope 22 years ago, providing the highest angular resolution CO atlas of this special area of the Galaxy. The data cover the area: -0${^{\circ}_{.}}$8 ≤ l ≤ +1${^{\circ}_{.}}$4 and -0${^{\circ}_{.}}$35 ≤ b ≤ +0${^{\circ}_{.}}$35 with a 15″ beamwidth. Total intensity ratios for CO J = 3-2/J = 1-0, 13CO/CO J = 1-0 and C18O/13CO J = 1-0, are 0.70 ± 0.06, 0.12 ± 0.01, and 0.14 ± 0.01, respectively. The high-resolution CO images show the fine structure of the molecular gas and enable us to identify a number of compact clouds with broad velocity widths, i.e., high-velocity compact clouds. We conducted a detailed comparison of our CO J = 1-0 data with the CO J = 3-2 data obtained with the James Clerk Maxwell Telescope to derive the distribution and kinematics of the highly excited gas. Three, out of four, of the previously identified high CO J = 3-2/J = 1-0 ratio areas at l = +1${^{\circ}_{.}}$3, 0${^{\circ}_{.}}$0, and -0${^{\circ}_{.}}$4 were confirmed with a higher spatial resolution. In addition to these, we identified several very compact, high CO J = 3-2/J = 1-0 spots with broad velocity widths for the first time. These are candidates for accelerated gas in the vicinity of invisible, point-like massive objects.
KW - Galaxy: center
KW - Galaxy: kinematics and dynamics
KW - ISM: molecules
KW - Surveys
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U2 - 10.1093/pasj/psy150
DO - 10.1093/pasj/psy150
M3 - Article
AN - SCOPUS:85081209937
VL - 71
JO - Publication of the Astronomical Society of Japan
JF - Publication of the Astronomical Society of Japan
SN - 0004-6264
M1 - S19
ER -