The H II region-molecular cloud complex W51

1979 ◽  
Vol 232 ◽  
pp. 451 ◽  
Author(s):  
S. L. Mufson ◽  
H. S. Liszt
Keyword(s):  
Molecular Cloud ◽  
H Ii Region ◽  
Cloud Complex

scholarly journals The H II region-molecular cloud complex W3 - Observations of CO, CS, and HCN

1980 ◽  
Vol 237 ◽  
pp. 711 ◽  
Author(s):  
H. R. Dickel ◽  
J. R. Dickel ◽  
W. J. Wilson ◽  
M. W. Werner
Keyword(s):  
Molecular Cloud ◽  
H Ii Region ◽  
Cloud Complex

scholarly journals Masers in SGR B2: Sites of Star-Forming Regions

1987 ◽  
Vol 115 ◽  
pp. 161-163 ◽  
Author(s):  
J. B. Whiteoak ◽  
F. F. Gardner ◽  
J. R. Forster ◽  
P. Palmer ◽  
V. Pankonin
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Molecular Clouds ◽  
Large Scale ◽  
Star Forming ◽  
Star Forming Regions ◽  
H Ii Region ◽  
Cloud Complex

H2CO and OH masers in the H II-region/molecular-cloud complex Sgr B2 have been observed with the VLA and combined with other observations of OH and H2O masers. It is found that groups of the masers and compact continuum components are located along a north-south line extending across the complex. The overall alignment suggests that star formation is being triggered by a single large-scale event such as an interaction between molecular clouds.

scholarly journals The Structure of the W49A Molecular Cloud Complex: Burst of Star Formation in the 105 M⊙ Core

1987 ◽  
Vol 115 ◽  
pp. 170-171
Author(s):  
Ryosuke Miyawaki ◽  
Masahiko Hayashi ◽  
Tetsuo Hasegawa
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Formation Rate ◽  
Maximum Level ◽  
Small Region ◽  
Sudden Increase ◽  
Core Mass ◽  
Order Of Magnitude ◽  
H Ii Region ◽  
Cloud Complex

We have observed the CS (J = 1-0), C34S (J = 1-0) and H51α emission toward the W49A molecular cloud complex in an area of 3'x 2′ (α x δ) with an angular resolution of 33″. The CS emitting region is 100″ x 80″ or 6.7 pc x 5.4 pc (α x δ) at the half maximum level. Although the CO emission is self-absorbed due to the foreground cold gas, the CS optical depth of the foreground gas is found to be small. Therefore, the two CS peaks at VLSR = 4 km s−1 and 12 km s−1 imply the presence of two dense molecular clouds toward W49A. The brighter 12 km s−1 cloud peaks 35″ southeast of W49A IRS, the infrared and H2O/OH maser sources associated with the compact H II region, while the 4 km s−1 cloud has a peak at W49A IRS. The hydrogen column density through the c34S emitting region is (0.3-1.7) x 1024 cm−2. The estimated core mass of the W49A molecular cloud is (0.5-2.5) x 104 M⊙. This mass is closely packed in a small region of 3.4 pc in diameter, and is about an order of magnitude larger than the virial mass of the system. The massive core will collapse within 10 years unless there is some special supporting mechanism. There was a sudden increase in the star formation rate 104– 105 years ago, suggesting a triggered burst of star formation in the core of W49A. The collision of two velocity clouds might have triggered the formation of this massive core and the burst of star formation.

scholarly journals Carbon-chain molecules in molecular outflows and Lupus I region – new producing region and new forming mechanism

2019 ◽  
Vol 488 (1) ◽  
pp. 495-511
Author(s):  
Yuefang Wu ◽  
Xunchuan Liu ◽  
Xi Chen ◽  
Lianghao Lin ◽  
Jinghua Yuan ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Molecular Cloud ◽  
Carbon Chain ◽  
Species Range ◽  
Chain Molecules ◽  
Forming Mechanism ◽  
Molecular Outflows ◽  
Chemical Models ◽  
Cloud Complex

Abstract Using the new equipment of the Shanghai Tian Ma Radio Telescope, we have searched for carbon-chain molecules (CCMs) towards five outflow sources and six Lupus I starless dust cores, including one region known to be characterized by warm carbon-chain chemistry (WCCC), Lupus I-1 (IRAS 15398-3359), and one TMC-1 like cloud, Lupus I-6 (Lupus-1A). Lines of HC3N J = 2 − 1, HC5N J = 6 − 5, HC7N J = 14 − 13, 15 − 14, 16 − 15, and C3S J = 3 − 2 were detected in all the targets except in the outflow source L1660 and the starless dust core Lupus I-3/4. The column densities of nitrogen-bearing species range from 1012 to 1014 cm−2 and those of C3S are about 1012 cm−2. Two outflow sources, I20582+7724 and L1221, could be identified as new carbon-chain-producing regions. Four of the Lupus I dust cores are newly identified as early quiescent and dark carbon-chain-producing regions similar to Lup I-6, which together with the WCCC source, Lup I-1, indicate that carbon-chain-producing regions are popular in Lupus I which can be regard as a Taurus-like molecular cloud complex in our Galaxy. The column densities of C3S are larger than those of HC7N in the three outflow sources I20582, L1221, and L1251A. Shocked carbon-chain chemistry is proposed to explain the abnormal high abundances of C3S compared with those of nitrogen-bearing CCMs. Gas-grain chemical models support the idea that shocks can fuel the environment of those sources with enough S+ thus driving the generation of S-bearing CCMs.

scholarly journals 13CO(J = 1-0) Observations of the Orion Molecular Cloud

1987 ◽  
Vol 115 ◽  
pp. 149-150
Author(s):  
K. Sugitani ◽  
Y. Fukui
Keyword(s):  
Millimeter Wave ◽  
High Velocity ◽  
Molecular Cloud ◽  
High Velocity Resolution ◽  
H Ii Region ◽  
Co Emission

We present new 13CO(J = 1-0) measurements of the Orion molecular cloud. The data were taken with the 4-m millimeter-wave telescope of Nagoya University with a beamwidth of 2.7′. The high velocity resolution of 0.1 km s−1 employed has revealed significant details of the 13CO emission toward the H II region.

scholarly journals Herschelfar-IR observations of the Chamaeleon molecular cloud complex

2012 ◽  
Vol 545 ◽  
pp. A145 ◽  
Author(s):  
E. Winston ◽  
N. L. J. Cox ◽  
T. Prusti ◽  
B. Merín ◽  
A. Ribas ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Cloud Complex

The Perseus OB2 Superbubble and the Taurus-Auriga-California-Perseus Molecular Cloud Loop

2021 ◽  
Author(s):  
Xuepeng Chen ◽  
Weihua Guo ◽  
Jiangcheng Feng ◽  
Yang Su ◽  
Yan Sun ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Cloud ◽  
Three Dimensional ◽  
Solar Neighborhood ◽  
Dimensional Structure ◽  
Wide Field ◽  
Star Forming ◽  
Stellar Feedback ◽  
History Of ◽  
Cloud Complex

Abstract Located at a distance of about 300 pc, Perseus OB2 (or Per~OB2 for short) is one of the major OB associations in the solar vicinity\cite{Zeeuw99,Belikov2002}, which has blown a supershell with a diameter of about 15 degree seen in the atomic hydrogen line surveys\cite{Sancisi1974,Heiles1984,Hartmann1997}. It was long considered that stellar feedback from the Per~OB2 association had formed a superbubble that swept up the surrounding interstellar medium into the observed supershell\cite{Bally2008}. Here we report the three-dimensional structure of the Per~OB2 superbubble, based on wide-field atomic hydrogen and molecular gas (traced by CO) surveys. The measured diameter of the superbubble is roughly 330 pc. Multiple atomic hydrogen shells/loops with expansion velocities of about 10 km/s are revealed in the superbubble, suggesting a complicated evolution history of the superbubble. Furthermore, the inspections of the morphology, kinematics and timescale of the Taurus-Auriga, California, and Perseus molecular clouds shows that the cloud complex is a super molecular cloud loop circling around and co-expanding with the Per~OB2 superbubble. We conclude that the Taurus-Auriga-California-Perseus loop, the largest star-forming molecular cloud complex in the solar neighborhood, is formed from the feedback of the Per~OB2 superbubble.

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