Molecular Clouds and Infrared Stellar Clusters in the Far Outer Galaxy

2002 ◽  
Vol 578 (1) ◽  
pp. 229-244 ◽  
Author(s):  
Ronald L. Snell ◽  
John M. Carpenter ◽  
Mark H. Heyer
Keyword(s):  
Molecular Clouds ◽  
Stellar Clusters

scholarly journals A 12CO Survey of the LMC with NANTEN

1999 ◽  
Vol 190 ◽  
pp. 61-66
Author(s):  
Y. Fukui ◽  
R. Abe ◽  
A. Hara ◽  
T. Hayakawa ◽  
S. Kato ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Cluster Formation ◽  
Hii Regions ◽  
Stellar Clusters ◽  
Giant Molecular Clouds

We have made a 12CO(J = 1−0) survey of the LMC with NANTEN. A sample of 55 giant molecular clouds has been identified and comparisons with stellar clusters, HII regions and SNRs are presented. The connection between the clouds and cluster formation is discussed.

scholarly journals Radio emission during the formation of stellar clusters in M 33

2020 ◽  
Vol 639 ◽  
pp. A27
Author(s):  
Edvige Corbelli ◽  
Jonathan Braine ◽  
Fatemeh S. Tabatabaei
Keyword(s):  
Radio Emission ◽  
Molecular Cloud ◽  
Molecular Clouds ◽  
Supernova Remnants ◽  
Line Emission ◽  
Radio Continuum ◽  
Stellar Clusters ◽  
Nonthermal Radio ◽  
Early Formation ◽  
5 Ghz

Aims. We investigate thermal and nonthermal radio emission associated with the early formation and evolution phases of young stellar clusters (YSCs) selected by their mid-infrared (MIR) emission at 24 μm in M 33. We consider regions in their early formation period, which are compact and totally embedded in the molecular cloud, and in the more evolved and exposed phase. Methods. Thanks to recent radio continuum surveys between 1.4 and 6.3 GHz we are able to find radio source counterparts to more than 300 star forming regions of M 33. We identify the thermal free–free component for YSCs and their associated molecular complexes using the Hα line emission. Results. A cross-correlation of MIR and radio continuum is established from bright to very faint sources, with the MIR-to-radio emission ratio that shows a slow radial decline throughout the M 33 disk. We confirm the nature of candidate embedded sources by recovering the associated faint radio continuum luminosities. By selecting exposed YSCs with reliable Hα flux, we establish and discuss the tight relation between Hα and the total radio continuum at 5 GHz over four orders of magnitude. This holds for individual YSCs as well as for the giant molecular clouds hosting them, and allows us to calibrate the radio continuum–star formation rate relation at small scales. On average, about half of the radio emission at 5 GHz in YSCs is nonthermal with large scatter. For exposed but compact YSCs and their molecular clouds, the nonthermal radio continuum fraction increases with source brightness, while for large HII regions the nonthermal fraction is lower and shows no clear trend. This has been found for YSCs with and without identified supernova remnants and underlines the possible role of massive stars in triggering particle acceleration through winds and shocks: these particles diffuse throughout the native molecular cloud prior to cloud dispersal.

scholarly journals A CO Survey of the LMC with NANTEN: III. Formation of Stellar Clusters and Evolution of Molecular Clouds

2001 ◽  
Vol 53 (6) ◽  
pp. 985-1001 ◽  
Author(s):  
Reiko Yamaguchi ◽  
Norikazu Mizuno ◽  
Akira Mizuno ◽  
Mónica Rubio ◽  
Rihei Abe ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Stellar Clusters

scholarly journals The physics and modes of star cluster formation: observations

2010 ◽  
Vol 368 (1913) ◽  
pp. 713-731 ◽  
Author(s):  
Charles J. Lada
Keyword(s):  
Present State ◽  
Molecular Clouds ◽  
Cluster Formation ◽  
Star Cluster ◽  
Stellar Clusters ◽  
Empirical Knowledge ◽  
Physical Processes ◽  
Subsequent Evolution ◽  
Cluster Systems ◽  
Infrared Wavelengths

Stellar clusters are born in cold and dusty molecular clouds and the youngest clusters are embedded to various degrees in a dusty dark molecular material. Such embedded clusters can be considered protocluster systems. The most deeply buried examples are so heavily obscured by dust that they are only visible at infrared wavelengths. These embedded protoclusters constitute the nearest laboratories for a direct astronomical investigation of the physical processes of cluster formation and early evolution. I review the present state of empirical knowledge concerning embedded-cluster systems and discuss the implications for understanding their formation and subsequent evolution to produce bound stellar clusters.

scholarly journals Molecular Clouds in the LMC Observed with NANTEN: II. Comparison with Stellar Clusters

1999 ◽  
Vol 190 ◽  
pp. 150-151
Author(s):  
R. Yamaguchi ◽  
R. Abe ◽  
A. Hara ◽  
T. Hayakawa ◽  
S. Kato ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Molecular Clouds ◽  
Detailed Comparison ◽  
Stellar Clusters ◽  
Giant Molecular Clouds

We have made 12CO(J=1−0) observations of the LMC with the NANTEN millimeter-wave telescope and identified about 100 distinct giant molecular clouds (GMCs). A detailed comparison of the GMCs with stellar clusters and a UV image is discussed.

scholarly journals Rise and fall of molecular clouds across the M 33 disk

2019 ◽  
Vol 622 ◽  
pp. A171 ◽  
Author(s):  
Edvige Corbelli ◽  
Jonathan Braine ◽  
Carlo Giovanardi
Keyword(s):  
Molecular Clouds ◽  
Line Emission ◽  
Molecular Gas ◽  
Stellar Clusters ◽  
Giant Molecular Clouds ◽  
Hii Region ◽  
Star Forming ◽  
Outer Disk ◽  
Low Mass ◽  
The Mean

We carried out deep searches for CO line emission in the outer disk of M 33, at R >  7 kpc, and examined the dynamical conditions that can explain variations in the mass distribution of the molecular cloud throughout the disk of M 33. We used the IRAM-30 m telescope to search for CO lines in the outer disk toward 12 faint mid-infrared (MIR) selected sources and in an area of the southern outer disk hosting MA1, a bright HII region. We detect narrow CO lines at the location of two MIR sources at galactocentric distances of about 8 kpc that are associated with low-mass young stellar clusters, and at four locations in the proximity of MA1. The paucity of CO lines at the location of weak MIR-selected sources probably arises because most of them are not star-forming sites in M 33, but background sources. Although very uncertain, the total molecular mass of the detected clouds around MA1 is lower than expected given the stellar mass of the cluster, because dispersal of the molecular gas is taking place as the HII region expands. The mean mass of the giant molecular clouds (GMCs) in M 33 decreases radially by a factor 2 from the center out to 4 kpc, then it stays constant until it drops at R >  7 kpc. We suggest that GMCs become more massive toward the center because of the fast rotation of the disk, which drives mass growth by coalescence of smaller condensations as they cross the arms. The analysis of both HI and CO spectral data gives the consistent result that corotation of the two main arms in this galaxy is at a radius of 4.7 ± 0.3 kpc, and spiral shock waves become subsonic beyond 3.9 kpc. Perturbations are quenched beyond 6.5 kpc, where CO lines have been detected only around sporadic condensations associated with UV and MIR emission.

scholarly journals Formation of Globular Clusters in Turbulent Molecular Clouds

2002 ◽  
Vol 207 ◽  
pp. 678-680
Author(s):  
Michael P. Geyer ◽  
Andreas Burkert
Keyword(s):  
Star Formation ◽  
Case Studies ◽  
Molecular Clouds ◽  
Globular Clusters ◽  
Stellar Clusters ◽  
Energy Feedback ◽  
The Future ◽  
Artificial Star

The formation of massive stellar clusters in turbulent molecular clouds is investigated. We include artificial star formation and energy feedback of newly born stars. The obtained systems are not likely to survive. Case studies to determine conditions necessary for forming bound clusters will be done in the future.

scholarly journals Molecular Clouds in the LMC Observed with NANTEN: III. Comparison with HII Regions

1999 ◽  
Vol 190 ◽  
pp. 130-131
Author(s):  
R. Abe ◽  
A. Hara ◽  
T. Hayakawa ◽  
S. Kato ◽  
A. Kawamura ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Hii Regions ◽  
Stellar Clusters ◽  
Giant Molecular Clouds

We have made 12CO(J=1-0) observations in the LMC with NANTEN, and compared the detected giant molecular clouds (GMCs) with HII regions and stellar clusters. It is found that ~ 80% of the GMCs are associated with HII regions. The results of comparisons of the GMCs with the HII regions and the stellar clusters are presented.

scholarly journals Giant molecular clouds and star formation in the Large Magellanic Cloud

2006 ◽  
Vol 2 (S237) ◽  
pp. 101-105
Author(s):  
A. Kawamura ◽  
T. Minamidani ◽  
Y. Mizuno ◽  
T. Onishi ◽  
N. Mizuno ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Cluster Formation ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Stellar Clusters ◽  
Giant Molecular Clouds ◽  
Surface Mass ◽  
Complete Survey ◽  
Physical Quantities

AbstractIn order to elucidate star formation in the Large Magellanic Cloud, a complete survey of the molecular clouds was carried out by NANTEN. In this work, we compare 230 giant molecular clouds (GMCs), whose physical quantities are well determined, with young clusters and Hii regions. We find that about 76% of the GMCs are actively forming stars or clusters, while 24% show no signs of massive star or cluster formation. Effects of supergiant shells (SGSs) on the formation of GMCs and stars are also studied. The number and surface mass densities of the GMCs are higher by a factor of 1.5–2 at the edge of the SGSs than elsewhere. It is also found that young stellar clusters are more actively formed in the GMCs facing to the center of the SGSs. These results are consistent with the previous studies by Yamaguchi et al. and suggest the formation of GMCs and the cluster is triggered by dynamical effects of the SGSs.

Sign in / Sign up

Export Citation Format

Share Document