Properties of dense cores in clustered massive star-forming regions at high angular resolution

ABSTRACT The ATOMS, standing for ALMA Three-millimeter Observations of Massive Star-forming regions, survey has observed 146 active star-forming regions with ALMA band 3, aiming to systematically investigate the spatial distribution of various dense gas tracers in a large sample of Galactic massive clumps, to study the roles of stellar feedback in star formation, and to characterize filamentary structures inside massive clumps. In this work, the observations, data analysis, and example science of the ATOMS survey are presented, using a case study for the G9.62+0.19 complex. Toward this source, some transitions, commonly assumed to trace dense gas, including CS J = 2−1, HCO+J = 1−0, and HCN J = 1−0, are found to show extended gas emission in low-density regions within the clump; less than 25 per cent of their emission is from dense cores. SO, CH3OH, H13CN, and HC3N show similar morphologies in their spatial distributions and reveal well the dense cores. Widespread narrow SiO emission is present (over ∼1 pc), which may be caused by slow shocks from large–scale colliding flows or H ii regions. Stellar feedback from an expanding H ii region has greatly reshaped the natal clump, significantly changed the spatial distribution of gas, and may also account for the sequential high-mass star formation in the G9.62+0.19 complex. The ATOMS survey data can be jointly analysed with other survey data, e.g. MALT90, Orion B, EMPIRE, ALMA_IMF, and ALMAGAL, to deepen our understandings of ‘dense gas’ star formation scaling relations and massive protocluster formation.

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Evidence of Evolution in the Dense Cores in Massive Star Forming Regions

Chinese Journal of Astronomy and Astrophysics ◽

10.1088/1009-9271/5/4/004 ◽

2005 ◽

Vol 5 (4) ◽

pp. 363-370

Author(s):

Jian-Jun Zhou ◽

Jarken Esimbek ◽

Ji-Xian Sun ◽

Bing-Gang Ju ◽

Jing-Jiang Sun

Keyword(s):

Massive Star ◽

Star Forming ◽

Star Forming Regions ◽

Dense Cores

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First Results from ATCA at Millimetre Wavelengths

Symposium - International Astronomical Union ◽

10.1017/s0074180900241685 ◽

2004 ◽

Vol 221 ◽

pp. 275-282

Author(s):

Vincent Minier

Keyword(s):

Star Formation ◽

Angular Resolution ◽

Galactic Plane ◽

Dust Emission ◽

Protoplanetary Disks ◽

High Angular Resolution ◽

Star Forming ◽

Star Forming Regions ◽

First Results ◽

Excellent Tool

The newly upgraded Australia Telescope Compact Array (ATCA) at millimetre wavelengths is the first millimetre interferometer to be built in the Southern Hemisphere. The full array will be operational in 2004-2005 and will provide arcsec angular resolution at 3 mm and 12 mm. This will be a unique instrument to study at high angular resolution the interstellar chemistry and more generally the star formation process, especially in the bulk of the galactic plane and in the Magellanic Clouds. The upgraded ATCA will also be an excellent tool to detect dust emission from nearby protoplanetary disks. In this paper I will present the first results from the upgraded ATCA at 3 mm and 12 mm. The result review will cover the topics of massive star formation and hot molecular cores dust emission from star-forming regions and detection of protoplanetary disks.

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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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Pre- and protostellar cores in the Rosette Nebula

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319002254 ◽

2018 ◽

Vol 14 (S345) ◽

pp. 371-372

Author(s):

R. Bögner ◽

T. Csengeri ◽

M. Wienen ◽

N. Schneider ◽

J. Montillaud ◽

...

Keyword(s):

Massive Star ◽

Filamentary Structure ◽

Star Forming ◽

Star Forming Regions ◽

Dense Cores ◽

Wide Range ◽

Rosette Nebula ◽

Low Mass ◽

Cloud Cores ◽

Gaining Insight

AbstractRecent theories on the formation of the Solar System turned the attention to the study of low mass cloud cores in massive star forming regions. The Rosette Molecular Cloud is a well-known star forming area having highly filamentary structure with dense cores covering a wide range of masses. These pre- and protostellar cores were observed by Herschel and key core properties were derived from its data. With the Effelsberg 100m telescope a sample of these cores with masses ranging between 3-40 M⊙ were observed in ammonia inversion lines. In this work we are examining the correlations between these two datasets with the aim of gaining insight of the processes behind the star formation of the region.

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HIGH-ANGULAR RESOLUTION DUST POLARIZATION MEASUREMENTS: SHAPEDB-FIELD LINES IN THE MASSIVE STAR-FORMING REGION ORION BN/KL

The Astrophysical Journal ◽

10.1088/0004-637x/717/2/1262 ◽

2010 ◽

Vol 717 (2) ◽

pp. 1262-1273 ◽

Cited By ~ 44

Author(s):

Ya-Wen Tang ◽

Paul T. P. Ho ◽

Patrick M. Koch ◽

Ramprasad Rao

Keyword(s):

Massive Star ◽

Angular Resolution ◽

High Angular Resolution ◽

Star Forming ◽

Polarization Measurements ◽

Field Lines

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Interferometric Studies of Low-Mass Protostars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311024860 ◽

2011 ◽

Vol 7 (S280) ◽

pp. 53-64

Author(s):

Jes K. Jørgensen

Keyword(s):

Angular Resolution ◽

Initial Conditions ◽

Spatial Scales ◽

High Angular Resolution ◽

Star Forming ◽

Star Forming Regions ◽

Wide Range ◽

Low Mass ◽

Near Future ◽

Opening Up

AbstractWith the advances in high angular resolution (sub)millimeter observations of low-mass protostars, windows of opportunities are opening up for very detailed studies of the molecular structure of star forming regions on wide range of spatial scales. Deeply embedded protostars provide an important laboratory to study the chemistry of star formation – providing the link between dense regions in molecular clouds from which stars are formed, i.e., the initial conditions and the end product in terms of, e.g., disk and planet formation. High angular resolution observations at (sub)millimeter wavelengths provide an important tool for studying the chemical composition of such low-mass protostars. They for example constrain the spatial molecular abundance variations – and can thereby identify which species are useful tracers of different components of the protostars at different evolutionary stages. In this review I discuss the possibilities and limitations of using high angular resolution (sub)millimeter interferometric observations for studying the chemical evolution of low-mass protostars – with a particular keen eye toward near-future ALMA observations.

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The Circumstellar Environment of Embedded Massive Stars

Highlights of Astronomy ◽

10.1017/s1539299600013083 ◽

2002 ◽

Vol 12 ◽

pp. 143-145 ◽

Cited By ~ 1

Author(s):

Lee G. Mundy ◽

Friedrich Wyrowski ◽

Sarah Watt

Keyword(s):

Massive Star ◽

Massive Stars ◽

Low Mass Stars ◽

Submillimeter Wavelength ◽

Star Forming ◽

Star Forming Regions ◽

Low Mass ◽

Circumstellar Environments ◽

Near Future

Millimeter and submillimeter wavelength images of massive star-forming regions are uncovering the natal material distribution and revealing the complexities of their circumstellar environments on size scales from parsecs to 100’s of AU. Progress in these areas has been slower than for low-mass stars because massive stars are more distant, and because they are gregarious siblings with different evolutionary stages that can co-exist even within a core. Nevertheless, observational goals for the near future include the characterization of an early evolutionary sequence for massive stars, determination if the accretion process and formation sequence for massive stars is similar to that of low-mass stars, and understanding of the role of triggering events in massive star formation.

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Millimetre wavelength methanol masers survey towards massive star forming regions

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307013051 ◽

2007 ◽

Vol 3 (S242) ◽

pp. 234-235

Author(s):

T. Umemoto ◽

N. Mochizuki ◽

K. M. Shibata ◽

D.-G. Roh ◽

H.-S. Chung

Keyword(s):

Detection Rate ◽

Massive Star ◽

Molecular Line ◽

Maser Emission ◽

Star Forming ◽

Methanol Maser ◽

Physical Conditions ◽

Star Forming Regions ◽

Methanol Masers ◽

Maser Sources

AbstractWe present the results of a mm wavelength methanol maser survey towards massive star forming regions. We have carried out Class II methanol maser observations at 86.6 GHz, 86.9 GHz and 107.0 GHz, simultaneously, using the Nobeyama 45 m telescope. We selected 108 6.7 GHz methanol maser sources with declinations above −25 degrees and fluxes above 20 Jy. The detection limit of maser observations was ~3 Jy. Of the 93 sources surveyed so far, we detected methanol emission in 25 sources (27%) and “maser” emission in nine sources (10%), of which thre “maser” sources are new detections. The detection rate for maser emission is about half that of a survey of the southern sky (Caswell et al. 2000). There is a correlation between the maser flux of 107 GHz and 6.7 GHz/12 GHz emission, but no correlation with the “thermal” (non maser) emission. From results of other molecular line observations, we found that the sources with methanol emission show higher gas temperatures and twice the detection rate of SiO emission. This may suggest that dust evaporation and destruction by shock are responsible for the high abundance of methanol molecules, one of the required physical conditions for maser emission.

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