VVV Search for New Young Clusters Towards the Star Forming Regions in Our Galaxy: First Results

Subarcsecond radio and infrared observations reveal a class of luminous, obscured, optically thick HII regions associated with extremely large young clusters in nearby starburst galaxies. VLA images show bright radio nebulae with ne ∼ 104 cm−3, densities characteristic of young Galactic compact HII regions. Excitation of the nebulae requires the presence of several thousand O stars within regions of 1-10 pc extent, corresponding to clusters containing 105–106 stars. The compact nebulae are also bright in the mid-infrared, and can for significant fractions of not only the total IR luminosity, but also the total bolometric luminosity, of the parent galaxies. The prototype for these “supernebulae” is the large, obscured cluster in the dwarf galaxy NGC 5253.

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Sardinia Radio Telescope (SRT) observations of Local Group dwarf galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318000704 ◽

2017 ◽

Vol 13 (S336) ◽

pp. 109-112

Author(s):

A. Tarchi ◽

P. Castangia ◽

G. Surcis ◽

A. Brunthaler ◽

K. M. Menten ◽

...

Keyword(s):

Radio Telescope ◽

Local Group ◽

Dwarf Galaxies ◽

Radio Continuum ◽

Maser Emission ◽

Star Forming ◽

Star Forming Regions ◽

First Results ◽

Ngc 6822 ◽

Almost All

AbstractThe dwarf galaxies in the Local Group (LG) reveal a surprising amount of spatial structuring. In particular, almost all non-satellite dwarfs belong to one of two planes that show a very pronounced symmetry. In order to determine if these structures in the LG are dynamically stable or, alternatively, if they only represent transient alignments, proper motion measurements of these galaxies are required. A viable method to derive proper motions is offered by VLBI studies of 22-GHz water (and 6.7-GHz methanol) maser lines in star-forming regions.In 2016, in the framework of the Early Science Program of the Sardinia Radio Telescope (SRT), we have conducted an extensive observational campaign to map the entire optical body of all the LG dwarf galaxies that belong to the two planes, at C and K band, in a search for methanol and water maser emission.Here, we outline the project and present its first results on 3 targets, NGC 6822, IC 1613, and WLM. While no luminous maser emission has been detected in these galaxies, a number of interesting weaker detections has been obtained, associated with particularly active star forming regions. In addition, we have produced deep radio continuum maps for these galaxies, aimed at investigating their star forming activity and providing an improved assessment of star formation rates in these galaxies.

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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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Rotational Velocities for B0-B3 Stars in Seven Young Clusters: Further Study of the Relationship between Rotation Speed and Density in Star-Forming Regions

The Astronomical Journal ◽

10.1086/511002 ◽

2007 ◽

Vol 133 (3) ◽

pp. 1092-1103 ◽

Cited By ~ 63

Author(s):

S. C. Wolff ◽

S. E. Strom ◽

D. Dror ◽

K. Venn

Keyword(s):

Rotation Speed ◽

Star Forming ◽

Star Forming Regions ◽

Young Clusters ◽

The Relationship

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THE CO(J=2-1)/CO(J=1-0) Luminosity Ratio in the Orion Giant Molecular Clouds

International Astronomical Union Colloquium ◽

10.1017/s0252921100019564 ◽

1994 ◽

Vol 140 ◽

pp. 232-233

Author(s):

Seiichi Sakamoto ◽

Tetsuo Hasegawa ◽

Masahiko Hayashi ◽

Toshihiro Handa ◽

Tomoharu Oka

Keyword(s):

Molecular Clouds ◽

Giant Molecular Clouds ◽

Large Area ◽

Active Star ◽

Star Forming ◽

Star Forming Regions ◽

First Results ◽

Galaxies Active

AbstractThe first results of large-area mapping observations of nearby giant molecular clouds in the CO(J=2-1) emission are presented. The CO(J=2-1)/CO(J=1-0) luminosity ratio is 0.75 and 0.62 for the Orion A and B clouds, respectively. These values are consistent with those observed typically in disks of galaxies (−0.6), and are significantly lower than large values (≳1) often observed in active star-forming regions in galaxies. Active star-forming regions in galaxies cannot be explained by ensemble of Orion-like GMCs; they may contain a different population of molecular clouds with high J-2-1/J=1-0 luminosity ratio.

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