Massive star formation in the Carina nebula complex and Gum 31. I. the Carina nebula complex

Abstract Herein, we present results from observations of the 12CO (J = 1–0), 13CO (J = 1–0), and 12CO (J = 2–1) emission lines toward the Carina nebula complex (CNC) obtained with the Mopra and NANTEN2 telescopes. We focused on massive-star-forming regions associated with the CNC including the three star clusters Tr 14, Tr 15, and Tr 16, and the isolated WR-star HD 92740. We found that the molecular clouds in the CNC are separated into mainly four clouds at velocities −27, −20, −14, and −8 km s−1. Their masses are 0.7 × 104 M⊙, 5.0 × 104 M⊙, 1.6 × 104 M⊙, and 0.7 × 104 M⊙, respectively. Most are likely associated with the star clusters, because of their high 12CO (J = 2–1)/12CO (J = 1–0) intensity ratios and their correspondence to the Spitzer 8 μm distributions. In addition, these clouds show the observational signatures of cloud–cloud collisions. In particular, there is a V-shaped structure in the position–velocity diagram and a complementary spatial distribution between the −20 km s−1 cloud and the −14 km s−1 cloud. Furthermore, we found that SiO emission, which is a tracer of a shocked molecular gas, is enhanced between the colliding clouds by using ALMA archive data. Based on these observational signatures, we propose a scenario wherein the formation of massive stars in the clusters was triggered by a collision between the two clouds. By using the path length of the collision and the assumed velocity separation, we estimate the timescale of the collision to be ∼1 Myr. This is comparable to the ages of the clusters estimated in previous studies.

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Properties of star forming regions in the Magellanic Clouds

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308028470 ◽

2008 ◽

Vol 4 (S256) ◽

pp. 215-226

Author(s):

Mónica Rubio

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Molecular Clouds ◽

Massive Star ◽

High Sensitivity ◽

Magellanic Clouds ◽

Molecular Gas ◽

Star Forming ◽

Star Forming Regions ◽

Low Metallicity

AbstractUnderstanding the process of star formation in low metallicity systems is one of the key studies in the early stages of galaxy evolution. The Magellanic Clouds, being the nearest examples of low metallicity systems, allow us to study in detail their star forming regions. As a consequence of their proximity we can resolve the molecular clouds and the regions of star formation individually. Therefore we can increase our knowledge of the interaction of young luminous stars with their environment. We will present results of multiwavelenghts studies of LMC and SMC massive star forming regions, which includes properties of the cold molecular gas, the embedded young population associated with molecular clouds, and the interaction of newly born stars with the surrounding interstellar medium, based on ASTE and APEX submillimeter observations complemented high sensitivity NIR groud based observations and Spitzer results.

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Spectra of Fast J-Shocks in Dense, Star-Forming Regions

Symposium - International Astronomical Union ◽

10.1017/s007418090009553x ◽

1987 ◽

Vol 115 ◽

pp. 202-202

Author(s):

C.F. McKee ◽

D. J. Hollenbach ◽

T. Jernigan

Keyword(s):

Shock Front ◽

Molecular Clouds ◽

Emission Lines ◽

Molecular Gas ◽

Stellar Winds ◽

Bipolar Outflows ◽

Molecular Emission ◽

Star Forming ◽

Star Forming Regions ◽

Weakly Ionized

Stellar winds, bipolar outflows, and supernovae generate strong shocks in molecular clouds. If the molecular gas is magnetized and weakly ionized, shocks slower than about 40-50 kms−1 (C-shocks) emit primarily in the infrared. Faster shocks, or shocks in a weakly magnetized or more highly ionized medium (J–shocks), emit primarily in the ultraviolet and are thus harder to detect in dusty regions. J–shocks in molecular gas are usually dissociative, so that molecular emission lines from such shocks are produced by molecules formed behind the shock front. Observations of fast shocks in molecular clouds can provide valuable insights into energetic events occurring within them.

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Shocked Molecular Hydrogen from Star Forming Regions

Symposium - International Astronomical Union ◽

10.1017/s0074180900095371 ◽

1987 ◽

Vol 115 ◽

pp. 181-181 ◽

Cited By ~ 2

Author(s):

Adair P. Lane ◽

John Bally

Keyword(s):

Shock Waves ◽

High Velocity ◽

Molecular Hydrogen ◽

Near Infrared ◽

Young Stars ◽

Emission Lines ◽

Molecular Gas ◽

Star Forming ◽

Star Forming Regions ◽

Post Shock

Near infrared (2 micron) emission lines from molecular hydrogen provide a powerful probe of the morphology and energetics of outflows associated with stellar birth. The H2 emission regions trace the location of shock waves formed when the high velocity outflow from young stars encounters dense quiescent gas. Since H2 is the dominant coolant of the hot post-shock molecular gas, the H2 lines provide a measure of the fraction of the total mechanical luminosity radiated away from the cloud.

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Dust emission in massive star-forming regions with PRONAOS: the Orion and M 17 molecular clouds

EAS Publications Series ◽

10.1051/eas:2002085 ◽

2002 ◽

Vol 4 ◽

pp. 263-263

Author(s):

X. Dupac ◽

Keyword(s):

Molecular Clouds ◽

Massive Star ◽

Dust Emission ◽

Star Forming ◽

Star Forming Regions

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Inefficient jet-induced star formation in Centaurus A

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731429 ◽

2017 ◽

Vol 608 ◽

pp. A98 ◽

Cited By ~ 9

Author(s):

Q. Salomé ◽

P. Salomé ◽

M.-A. Miville-Deschênes ◽

F. Combes ◽

S. Hamer

Keyword(s):

Star Formation ◽

Positive Feedback ◽

Molecular Clouds ◽

Milky Way ◽

Data Cube ◽

Molecular Gas ◽

Star Forming ◽

Star Forming Regions ◽

Co Emission ◽

Centaurus A

NGC 5128 (Centaurus A) is one of the best targets to study AGN feedback in the local Universe. At 13.5 kpc from the galaxy, optical filaments with recent star formation lie along the radio jet direction. This region is a testbed for positive feedback, here through jet-induced star formation. Atacama Pathfinder EXperiment (APEX) observations have revealed strong CO emission in star-forming regions and in regions with no detected tracers of star formation activity. In cases where star formation is observed, this activity appears to be inefficient compared to the Kennicutt-Schmidt relation. We used the Atacama Large Millimeter/submillimeter Array (ALMA) to map the 12CO(1–0) emission all along the filaments of NGC 5128 at a resolution of 1.3′′ ~ 23.8pc. We find that the CO emission is clumpy and is distributed in two main structures: (i) the Horseshoe complex, located outside the HI cloud, where gas is mostly excited by shocks and where no star formation is observed, and (ii) the Vertical filament, located at the edge of the HI shell, which is a region of moderate star formation. We identified 140 molecular clouds using a clustering method applied to the CO data cube. A statistical study reveals that these clouds have very similar physical properties, such as size, velocity dispersion, and mass, as in the inner Milky Way. However, the range of radius available with the present ALMA observations does not enable us to investigate whether or not the clouds follow the Larson relation. The large virial parameter αvir of the clouds suggests that gravity is not dominant and clouds are not gravitationally unstable. Finally, the total energy injection in the northern filaments of Centaurus A is of the same order as in the inner part of the Milky Way. The strong CO emission detected in the northern filaments is an indication that the energy injected by the jet acts positively in the formation of dense molecular gas. The relatively high virial parameter of the molecular clouds suggests that the injected kinetic energy is too strong for star formation to be efficient. This is particularly the case in the horseshoe complex, where the virial parameter is the largest and where strong CO is detected with no associated star formation. This is the first evidence of AGN positive feedback in the sense of forming molecular gas through shocks, associated with low star formation efficiency due to turbulence injection by the interaction with the radio jet.

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Physics and chemistry of hot molecular cores

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307001378 ◽

2006 ◽

Vol 2 (S237) ◽

pp. 148-154 ◽

Cited By ~ 3

Author(s):

H. Beuther

Keyword(s):

Accretion Disks ◽

Massive Star ◽

Small Scale ◽

High Angular Resolution ◽

Physical Parameters ◽

Molecular Gas ◽

Star Forming ◽

Star Forming Regions ◽

Molecular Lines ◽

The Right

AbstractYoung massive star-forming regions are known to produce hot molecular gas cores (HMCs) with a rich chemistry. While this chemistry is interesting in itself, it also allows to investigate important physical parameters. I will present recent results obtained with high-angular-resolution interferometers disentangling the small-scale structure and complexity of various molecular gas components. Early attempts to develop a chemical evolutionary sequence are discussed. Furthermore, I will outline the difficulty to isolate the right molecular lines capable to unambiguously trace potential massive accretion disks.

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The massive star Initial Mass function

Symposium - International Astronomical Union ◽

10.1017/s007418090021303x ◽

2003 ◽

Vol 212 ◽

pp. 642-651 ◽

Cited By ~ 3

Author(s):

Daniel Schaerer

Keyword(s):

Massive Star ◽

Current Knowledge ◽

Star Clusters ◽

Mass Function ◽

Initial Mass Function ◽

H Ii Regions ◽

Star Forming ◽

Star Forming Regions ◽

Super Star Clusters ◽

The Imf

We review our current knowledge on the IMF in nearby environments, massive star forming regions, super star clusters, starbursts and alike objects from studies of integrated light, and discuss the various techniques used to constrain the IMF. In most cases, including UV-optical studies of stellar features and optical-IR analysis of nebular emission, the data is found to be compatible with a ‘universal’ Salpeter-like IMF with a high upper mass cut-off over a large metallicity range. In contrast, near-IR observations of nuclear starbursts and LIRG show indications of a lowerMupand/or a steeper IMF slope, for which no alternate explanation has yet been found. Also, dynamical mass measurements of seven super star clusters provide so far no simple picture of the IMF. Finally, we present recent results of a direct stellar probe of the upper end of the IMF in metal-rich H ii regions, showing no deficiency of massive stars at high metallicity, and determining a lower limit ofMup≳ 60 – 90 M⊙.

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