Multi-generation massive star-formation in NGC3576
arXiv:0909.1223 · doi:10.1051/0004-6361/200811358
Abstract
Recent 1.2-mm continuum observations have shown the giant HII region NGC3576 to be embedded in the centre of an extended filamentary dust-cloud. The bulk of the filament away from the HII region contains a number of clumps seen only at (sub-)millimetre wavelengths and which may host massive protostellar objects at a very early stage of evolution. We have used the Australia Telescope Compact Array (ATCA) to image the cloud for the NH3(1,1), (2,2) and (4,4) transitions, 22 GHz water masers, and 23 GHz continuum emission. We also utilised the 22-m Mopra antenna to map the region for the molecular lines 13CO (1-0), C18O (1-0), HCO+ (1-0), H13CO+ (1-0), CS (1-0) and N2H+ (1-0).The HII region is observed to be expanding into the molecular cloud, sweeping up a clumpy shell of gas, while the central star cluster is dispersing the molecular gas to the east. Temperatures are highest adjacent to the central HII region, indicating that the embedded cluster of young stars there is heating the gas. Six new water masers were detected in the arms of the filament, all associated with NH3 emission peaks, confirming that star-formation has begun within these cores. Core masses range from 5 to 516 solar masses and most appear to be gravitationally bound. Complementary results by André et al. (2008) imply that seven cores will go on to form massive stars between 15 and 50 solar masses. The large scale velocity structure of the filament is smooth, but at least one clump shows the signature of inward gas motions via asymmetries in the NH3 (1,1) line profiles. The same clump exhibits an enhanced abundance of N2H+, which coupled with an absence of CO indicates depletion onto the dust grain surface. The HII region at the heart of NGC3576 is potentially triggering the formation of massive stars in the bulk of the associated cloud.
22 pages, 16 figures
References in corpus (27)
- Embedded Clusters in Molecular Clouds
- Interpreting Spectral Energy Distributions from Young Stellar Objects. II. Fitting observed SEDs using a large grid of pre-computed models
- Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A grid of 200,000 YSO model SEDs
- Physical Conditions in Regions of Star Formation
- Infrared Dark Clouds: precursors to star clusters
- Pulsar rotation measures and the large-scale structure of Galactic magnetic field
- N2H+ and C18O Depletion in a Cold Dark Cloud
- A Warped Accretion Disk and Wide Angle Outflow in the Inner Parsec of the Circinus Galaxy
- Ammonia in Infrared Dark Clouds
- Molecular Evolution in Collapsing Prestellar Cores
- CH3OH and H2O masers in high-mass star-forming regions
- Triggered massive-star formation on the borders of Galactic HII regions. II. Evidence for the collect and collapse process around RCW 79
- Probing the formation of intermediate- to high-mass stars in protoclusters: A detailed millimeter study of the NGC 2264 clumps
- Star formation around RCW 120, the perfect bubble
- Millimetre continuum observations of southern massive star formation regions. I. SIMBA observations of cold cores
- N2H+(1-0) survey of massive molecular cloud cores
- Triggered massive-star formation on the borders of Galactic HII regions. IV- Star formation at the periphery of Sh2-212
- The HCO+ emission excess in bipolar outflows
- NH3 Observations of the Infrared Dark Cloud G28.34+0.06
- Magnetic fields in massive star forming regions
- A GLIMPSE of Star Formation in the Giant H II Region RCW 49
- NGC 3576 and NGC 3603: Two Luminous Southern HII Regions Observed at High Resolution with the Australia Telescope Compact Array
- First 450-micron dust continuum mapping of the massive star-forming region NGC 3576 with the P-ArTeMiS bolometer camera
- Radio continuum and molecular line observations of four bright-rimmed clouds
- Chemical differentiation in regions of high-mass star formation I. CS, dust and N2H^+ in southern sources
- L-band (3.5 micron) IR-excess in massive star formation, II. RCW 57/NGC 3576
- Gemini Mid-Infrared Imaging of Massive Young Stellar Objects in NGC 3576
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- Chemical Evolution in High-Mass Star-Forming Regions: Results from the MALT90 Survey
- The H2O southern Galactic Plane Survey(HOPS): NH3 (1,1) and (2,2) catalogues
- The Free-Fall time of finite Sheets and Filaments
- Initial phases of massive star formation in high infrared extinction clouds. II. Infall and onset of star formation
- 3D simulations of pillars formation around HII regions: the importance of shock curvature
- Feedback from Winds and Supernovae in Massive Stellar Clusters - II. X-Ray Emission
- Dense gas in IRAS 20343+4129: an ultracompact HII region caught in the act of creating a cavity
- Radiative transfer of ionizing radiation through gas and dust: stellar source case
- Understanding the links among magnetic fields, filament, the bipolar bubble, and star formation in RCW57A using NIR polarimetry
- ALMA Observations of the massive molecular outflow G331.512-0.103 II: physical properties, kinematics, and geometry modeling
- Star-forming Region Sh 2-233IR I. Deep NIR Observations toward the Embedded Stellar Clusters
- Pilot Observations for MALT-45: A Galactic Plane Survey at 7mm
- Physical Properties and Kinematics of Dense Cores Associated with Regions of Massive Star Formation from the Southern Sky