scholarly journals FOREST unbiased Galactic plane imaging survey with the Nobeyama 45 m telescope (FUGIN). VIII. Possible evidence of cloud–cloud collisions triggering high-mass star formation in the giant molecular cloud M 16 (Eagle Nebula)

2020 ◽  
Author(s):  
Atsushi Nishimura ◽  
Shinji Fujita ◽  
Mikito Kohno ◽  
Daichi Tsutsumi ◽  
Tetsuhiro Minamidani ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Velocity Structure ◽  
Galactic Plane ◽  
High Mass ◽  
Mass Star ◽  
Collision Event ◽  
Giant Molecular Cloud ◽  
Eagle Nebula ◽  
H Ii Region

Abstract M 16, the Eagle Nebula, is an outstanding H ii region which exhibits extensive high-mass star formation and hosts remarkable “pillars.” We herein obtained new 12COJ = 1–0 data for the region observed with NANTEN2, which were combined with the 12COJ = 1–0 data obtained using the FOREST unbiased galactic plane imaging with Nobeyama 45 m telescope (FUGIN) survey. These observations revealed that a giant molecular cloud (GMC) of ∼1.3 × 105 M⊙ is associated with M 16, which extends for 30 pc perpendicularly to the galactic plane, at a distance of 1.8 kpc. This GMC can be divided into the northern (N) cloud, the eastern (E) filament, the southeastern (SE) cloud, the southeastern (SE) filament, and the southern (S) cloud. We also found two velocity components (blueshifted and redshifted components) in the N cloud. The blueshifted component shows a ring-like structure, and the redshifted one coincides with the intensity depression of the ring-like structure. The position–velocity diagram of the components showed a V-shaped velocity feature. The spatial and velocity structures of the cloud indicated that two different velocity components collided with each other at a relative velocity of 11.6 km s−1. The timescale of the collision was estimated to be ∼4 × 105 yr. The collision event reasonably explains the formation of the O9V star ALS 15348, as well as the shape of the Spitzer bubble N19. A similar velocity structure was found in the SE cloud, which is associated with the O7.5V star HD 168504. In addition, the complementary distributions of the two velocity components found in the entire GMC suggested that the collision event occurred globally. On the basis of the above results, we herein propose a hypothesis that the collision between the two components occurred sequentially over the last several 106 yr and triggered the formation of O-type stars in the NGC 6611 cluster in M 16.

scholarly journals Dense cores and star formation in the giant molecular cloud Vela C

2019 ◽  
Vol 628 ◽  
pp. A110 ◽  
Author(s):  
F. Massi ◽  
A. Weiss ◽  
D. Elia ◽  
T. Csengeri ◽  
E. Schisano ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Galactic Plane ◽  
Mass Function ◽  
Initial Mass Function ◽  
High Mass ◽  
Mass Star ◽  
Ancillary Data ◽  
Core Mass ◽  
Giant Molecular Cloud

Context. The Vela Molecular Ridge is one of the nearest (700 pc) giant molecular cloud (GMC) complexes hosting intermediate-mass (up to early B, late O stars) star formation, and is located in the outer Galaxy, inside the Galactic plane. Vela C is one of the GMCs making up the Vela Molecular Ridge, and exhibits both sub-regions of robust and sub-regions of more quiescent star formation activity, with both low- and intermediate(high)-mass star formation in progress. Aims. We aim to study the individual and global properties of dense dust cores in Vela C, and aim to search for spatial variations in these properties which could be related to different environmental properties and/or evolutionary stages in the various sub-regions of Vela C. Methods. We mapped the submillimetre (345 GHz) emission from vela C with LABOCA (beam size ~19′′2, spatial resolution ~0.07 pc at 700 pc) at the APEX telescope. We used the clump-finding algorithm CuTEx to identify the compact submillimetre sources. We also used SIMBA (250 GHz) observations, and Herschel and WISE ancillary data. The association with WISE red sources allowed the protostellar and starless cores to be separated, whereas the Herschel dataset allowed the dust temperature to be derived for a fraction of cores. The protostellar and starless core mass functions (CMFs) were constructed following two different approaches, achieving a mass completeness limit of 3.7 M⊙. Results. We retrieved 549 submillimetre cores, 316 of which are starless and mostly gravitationally bound (therefore prestellar in nature). Both the protostellar and the starless CMFs are consistent with the shape of a Salpeter initial mass function in the high-mass part of the distribution. Clustering of cores at scales of 1–6 pc is also found, hinting at fractionation of magnetised, turbulent gas.

scholarly journals Ammonia towards dust clumps in the giant molecular cloud associated with RCW 106

2012 ◽  
Vol 8 (S292) ◽  
pp. 50-50
Author(s):  
Vicki Lowe ◽  
Maria R. Cunningham ◽  
James S. Urquhart ◽  
Shinji Horiuchi
Keyword(s):  
Star Formation ◽  
Radio Telescope ◽  
Molecular Cloud ◽  
Galactic Plane ◽  
High Mass ◽  
Mass Star ◽  
Giant Molecular Clouds ◽  
Molecular Line ◽  
Star Forming ◽  
Star Formation Regions

AbstractHigh-mass stars are known to be born within giant molecular clouds (GMCs); However, the exact processes involved in forming a high-mass star are still not well understood. It is clear that high-mass stars do not form in isolation, and that the processes surrounding high-mass star formation may affect the environment of the entire molecular cloud. We are studying the GMC associated with RCW 106 (G333), which is one of the most active massive-star formation regions in the Galactic plane. This GMC, located at l = 333° b = − 0.5°, has been mapped in over 20 molecular line transitions with the Mopra radio telescope (83-110 GHz), in Australia, and with the Swedish-ESO Submillimeter Telescope (SEST) in the 1.2 mm cool dust continuum. The region is also within the Spitzer GLIMPSE infrared survey (3.6, 4.5, 5.8, and 8.0 μm) area. We have decomposed the dust continuum using a clump-finding algorithm (CLUMPFIND), and are using the multiple molecular line traditions from the Mopra radio telescope to classify the type and stage of star formation taking place therein. Having accurate physical temperatures of the star forming clumps is essential to constrain other parameters to within useful limits. To achieve this, we have obtained pointed NH3 observations from the Tidbinbilla 70-m radio telescope, in Australia, towards these clumps.

scholarly journals ALMA CO observations of a giant molecular cloud in M 33: Evidence for high-mass star formation triggered by cloud–cloud collisions

2020 ◽  
Author(s):  
Hidetoshi Sano ◽  
Kisetsu Tsuge ◽  
Kazuki Tokuda ◽  
Kazuyuki Muraoka ◽  
Kengo Tachihara ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Molecular Clouds ◽  
Line Emission ◽  
High Mass ◽  
H Ii Regions ◽  
Mass Star ◽  
Star Forming ◽  
Spatially Resolved ◽  
Giant Molecular Cloud

Abstract We report the first evidence for high-mass star formation triggered by collisions of molecular clouds in M 33. Using the Atacama Large Millimeter/submillimeter Array, we spatially resolved filamentary structures of giant molecular cloud 37 in M 33 using 12CO(J = 2–1), 13CO(J = 2–1), and C18O(J = 2–1) line emission at a spatial resolution of ∼2 pc. There are two individual molecular clouds with a systematic velocity difference of ∼6 km s−1. Three continuum sources representing up to ∼10 high-mass stars with spectral types of B0V–O7.5V are embedded within the densest parts of molecular clouds bright in the C18O(J = 2–1) line emission. The two molecular clouds show a complementary spatial distribution with a spatial displacement of ∼6.2 pc, and show a V-shaped structure in the position–velocity diagram. These observational features traced by CO and its isotopes are consistent with those in high-mass star-forming regions created by cloud–cloud collisions in the Galactic and Magellanic Cloud H ii regions. Our new finding in M 33 indicates that cloud–cloud collision is a promising process for triggering high-mass star formation in the Local Group.

scholarly journals High mass Star formation in the giant molecular cloud NGC 6334: an infrared view

2005 ◽  
Vol 1 (S227) ◽  
pp. 291-296 ◽  
Author(s):  
P. Persi ◽  
M. Tapia ◽  
M. Roth ◽  
M. Gómez ◽  
A. R. Marenzi
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
High Mass ◽  
Mass Star ◽  
Giant Molecular Cloud ◽  
Ngc 6334

scholarly journals FOREST unbiased Galactic plane imaging survey with the Nobeyama 45 m telescope (FUGIN). VI. Dense gas and mini-starbursts in the W 43 giant molecular cloud complex

2020 ◽  
Author(s):  
Mikito Kohno ◽  
Kengo Tachihara ◽  
Kazufumi Torii ◽  
Shinji Fujita ◽  
Atsushi Nishimura ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Large Scale ◽  
Galactic Plane ◽  
High Mass ◽  
Mass Star ◽  
Dense Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Giant Molecular Cloud ◽  
Cloud Complex

Abstract We performed new large-scale 12CO, 13CO, and C18O J = 1–0 observations of the W 43 giant molecular cloud complex in the tangential direction of the Scutum arm (l ∼30°) as a part of the FUGIN project. The low-density gas traced by 12CO is distributed over 150 pc × 100 pc (l × b), and has a large velocity dispersion (20–30 km s−1). However, the dense gas traced by C18O is localized in the W 43 Main, G30.5, and W 43 South (G29.96−0.02) high-mass star-forming regions in the W 43 giant molecular cloud (GMC) complex, which have clumpy structures. We found at least two clouds with a velocity difference of ∼10–20 km s−1, both of which are likely to be physically associated with these high-mass star-forming regions based on the results of high 13CO J = 3–2 to J = 1–0 intensity ratio and morphological correspondence with the infrared dust emission. The velocity separation of these clouds in W 43 Main, G30.5, and W 43 South is too large for each cloud to be gravitationally bound. We also revealed that the dense gas in the W 43 GMC has a high local column density, while “the current SFE” (star formation efficiency) of the entire GMC is low ($\sim\!\! 4\%$) compared with the W 51 and M 17 GMC. We argue that the supersonic cloud–cloud collision hypothesis can explain the origin of the local mini-starbursts and dense gas formation in the W 43 GMC complex.

scholarly journals GASTON: Galactic Star Formation with NIKA2. Evidence for the mass growth of star-forming clumps

2021 ◽  
Author(s):  
A J Rigby ◽  
N Peretto ◽  
R Adam ◽  
P Ade ◽  
M Anderson ◽  
...  
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Galactic Plane ◽  
High Sensitivity ◽  
High Mass ◽  
Evolutionary Stage ◽  
Mass Star ◽  
Mass Growth ◽  
Star Forming ◽  
Compact Source

Abstract Determining the mechanism by which high-mass stars are formed is essential for our understanding of the energy budget and chemical evolution of galaxies. By using the New IRAM KIDs Array 2 (NIKA2) camera on the Institut de Radio Astronomie Millimétrique (IRAM) 30-m telescope, we have conducted high-sensitivity and large-scale mapping of a fraction of the Galactic plane in order to search for signatures of the transition between the high- and low-mass star-forming modes. Here, we present the first results from the Galactic Star Formation with NIKA2 (GASTON) project, a Large Programme at the IRAM 30-m telescope which is mapping ≈2 deg2 of the inner Galactic plane (GP), centred on ℓ = 23${_{.}^{\circ}}$9, b = 0${_{.}^{\circ}}$05, as well as targets in Taurus and Ophiuchus in 1.15 and 2.00 mm continuum wavebands. In this paper we present the first of the GASTON GP data taken, and present initial science results. We conduct an extraction of structures from the 1.15 mm maps using a dendrogram analysis and, by comparison to the compact source catalogues from Herschel survey data, we identify a population of 321 previously-undetected clumps. Approximately 80 per cent of these new clumps are 70 μm-quiet, and may be considered as starless candidates. We find that this new population of clumps are less massive and cooler, on average, than clumps that have already been identified. Further, by classifying the full sample of clumps based upon their infrared-bright fraction – an indicator of evolutionary stage – we find evidence for clump mass growth, supporting models of clump-fed high-mass star formation.

scholarly journals Triggered high-mass star formation in the H ii region W 28 A2: A cloud–cloud collision scenario

2020 ◽  
Author(s):  
Katsuhiro Hayashi ◽  
Satoshi Yoshiike ◽  
Rei Enokiya ◽  
Shinji Fujita ◽  
Rin Yamada ◽  
...  
Keyword(s):  
Star Formation ◽  
Intensity Ratio ◽  
Molecular Clouds ◽  
Early Stage ◽  
Infrared Emission ◽  
Radio Continuum ◽  
High Mass ◽  
Continuum Emission ◽  
Mass Star ◽  
H Ii Region

Abstract We report on a study of the high-mass star formation in the H ii region W 28 A2 by investigating the molecular clouds that extend over ∼5–10 pc from the exciting stars using the 12CO and 13CO (J = 1–0) and 12CO (J = 2–1) data taken by NANTEN2 and Mopra observations. These molecular clouds consist of three velocity components with CO intensity peaks at VLSR ∼ −4 km s−1, 9 km s−1, and 16 km s−1. The highest CO intensity is detected at VLSR ∼ 9 km s−1, where the high-mass stars with spectral types O6.5–B0.5 are embedded. We found bridging features connecting these clouds toward the directions of the exciting sources. Comparisons of the gas distributions with the radio continuum emission and 8 μm infrared emission show spatial coincidence/anti-coincidence, suggesting physical associations between the gas and the exciting sources. The 12CO J = 2–1 to 1–0 intensity ratio shows a high value (≳0.8) toward the exciting sources for the −4 km s−1 and +9 km s−1 clouds, possibly due to heating by the high-mass stars, whereas the intensity ratio at the CO intensity peak (VLSR ∼ 9 km s−1) decreases to ∼0.6, suggesting self absorption by the dense gas in the near side of the +9 km s−1 cloud. We found partly complementary gas distributions between the −4 km s−1 and +9 km s−1 clouds, and the −4 km s−1 and +16 km s−1 clouds. The exciting sources are located toward the overlapping region in the −4 km s−1 and +9 km s−1 clouds. Similar gas properties are found in the Galactic massive star clusters RCW 38 and NGC 6334, where an early stage of cloud collision to trigger the star formation is suggested. Based on these results, we discuss the possibility of the formation of high-mass stars in the W 28 A2 region being triggered by cloud–cloud collision.

scholarly journals EVOLUTION OF MAGNETIC FIELDS IN HIGH MASS STAR FORMATION: SUBMILLIMETER ARRAY DUST POLARIZATION IMAGE OF THE ULTRACOMPACT H II REGION G5.89–0.39

2009 ◽  
Vol 695 (2) ◽  
pp. 1399-1412 ◽  
Author(s):  
Ya-Wen Tang ◽  
Paul T. P. Ho ◽  
Josep Miquel Girart ◽  
Ramprasad Rao ◽  
Patrick Koch ◽  
...  
Keyword(s):  
Star Formation ◽  
Magnetic Fields ◽  
High Mass ◽  
Mass Star ◽  
Polarization Image ◽  
H Ii Region

scholarly journals High-Mass Star and Massive Cluster Formation in the Milky Way

2018 ◽  
Vol 56 (1) ◽  
pp. 41-82 ◽  
Author(s):  
Frédérique Motte ◽  
Sylvain Bontemps ◽  
Fabien Louvet
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Galactic Plane ◽  
Cluster Formation ◽  
Theoretical Models ◽  
High Mass ◽  
High Angular Resolution ◽  
Mass Star ◽  
Star Forming ◽  
Massive Cluster

This review examines the state-of-the-art knowledge of high-mass star and massive cluster formation, gained from ambitious observational surveys, which acknowledges the multiscale characteristics of these processes. After a brief overview of theoretical models and main open issues, we present observational searches for the evolutionary phases of high-mass star formation, first among high-luminosity sources and more recently among young massive protostars and the elusive high-mass prestellar cores. We then introduce the most likely evolutionary scenario for high-mass star formation, which emphasizes the link of high-mass star formation to massive cloud and cluster formation. Finally, we introduce the first attempts to search for variations of the star-formation activity and cluster formation in molecular cloud complexes in the most extreme star-forming sites and across the Milky Way. The combination of Galactic plane surveys and high–angular resolution images with submillimeter facilities such as Atacama Large Millimeter Array (ALMA) are prerequisites to make significant progress in the forthcoming decade.

scholarly journals CORNISH: A 5 GHz VLA survey of the Galactic plane

2009 ◽  
Vol 5 (H15) ◽  
pp. 781-781
Author(s):  
Cormac R. Purcell ◽  
Melvin G. Hoare ◽  
Keyword(s):  
Star Formation ◽  
Galactic Plane ◽  
Radio Continuum ◽  
High Mass ◽  
Mass Star ◽  
Multi Wavelength ◽  
Region 10 ◽  
5 Ghz ◽  
Infrared Survey ◽  
Key Questions

AbstractThe CORNISH (Co-Ordinated Radio ‘N’ Infrared Survey for High-mass star formation) project is the radio continuum part of a series of multi-wavelength surveys of the Galactic Plane that focus on the northern GLIMPSE-I region (10° < l <65°, |b| < 1°) observed by the SPITZER satellite in the mid-infrared (Churchwell et al. 2009). CORNISH has delivered a complementary 5 GHz arcsecond resolution, radio-continuum survey to address key questions in high-mass star formation as well as many other areas of astrophysics.

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