scholarly journals Combination of CN(1-0), HCN(1-0), and HNC(1-0): A possible indicator for a high-mass star formation sequence in the Milky Way

2015 ◽  
Vol 576 ◽  
pp. A131 ◽  
Author(s):  
X. H. Han ◽  
J. J. Zhou ◽  
J. Z. Wang ◽  
J. Esimbek ◽  
J. S. Zhang ◽  
...  
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
High Mass ◽  
Mass Star

scholarly journals The JCMT Legacy Survey: Mapping the Milky Way in the Submillimetre

2009 ◽  
Vol 5 (H15) ◽  
pp. 797-797
Author(s):  
Antonio Chrysostomou ◽  
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
High Mass ◽  
Mass Star ◽  
Valuable Resource ◽  
Spectral Window ◽  
Multi Wavelength ◽  
Second Year ◽  
Near Future

AbstractThe JCMT Legacy Survey (JLS) is an ambitious programme of independent surveys to study our Galaxy and universe in the submillimetre (λ = 450 − 850 μm) from the summit of Mauna Kea, Hawaii. With its scientific breadth and unique spectral window, it is clear that the JLS will have a significant impact on star formation studies in the near future and beyond. Its complementarity with other surveys (e.g. Spitzer, Herschel) will make the JLS a very valuable resource for multi-wavelength studies for low and high-mass star formation across the Milky Way. The JLS is currently in its second year of operation.

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 High-mass stars in Milky Way clusters

2016 ◽  
Vol 12 (S329) ◽  
pp. 271-278
Author(s):  
Ignacio Negueruela
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Theoretical Models ◽  
Open Clusters ◽  
High Mass ◽  
Mass Star ◽  
Formation And Evolution

AbstractYoung open clusters are our laboratories for studying high-mass star formation and evolution. Unfortunately, the information that they provide is difficult to interpret, and sometimes contradictory. In this contribution, I present a few examples of the uncertainties that we face when confronting observations with theoretical models and our own assumptions.

scholarly journals Molecular Gas Kinematics and High-Mass Star Formation in the Spiral Arms of the Milky Way

2004 ◽  
Vol 191 ◽  
pp. 143-144
Author(s):  
A. Luna ◽  
L. Carrasco ◽  
L. Ortega ◽  
L. Bronfman ◽  
O. Yam
Keyword(s):  
Star Formation ◽  
Rigid Body ◽  
Large Scale ◽  
Milky Way ◽  
Stellar System ◽  
High Mass ◽  
Rotational Line ◽  
Molecular Gas ◽  
Mass Star ◽  
Spiral Arms

AbstractWe study the kinematic of the molecular gas using observations of the rotational line 12CO(J=1→0), and also the star formation traced by Ultra-Compact HII regions in the IV galactic quadrant (270° ≤ l ≤ 360°). Our results show that there is a connection between 1) high-mass star formation in the spiral arms of the Milky Way, 2) molecular gas of high column density, and 3) the large-scale rigid-body-like motion of the gas. The large-scale rigid-body-like motions observed in the arms imply that there is less angular momentum to dissipate in the formation processes of stellar systems. We show a multiple stellar system under study, embedded in its parent molecular cloud in the Carina arm region.

scholarly journals The local spiral structure of the Milky Way

2016 ◽  
Vol 2 (9) ◽  
pp. e1600878 ◽  
Author(s):  
Ye Xu ◽  
Mark Reid ◽  
Thomas Dame ◽  
Karl Menten ◽  
Nobuyuki Sakai ◽  
...  
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Spiral Structure ◽  
Formation Rate ◽  
Great Distance ◽  
High Mass ◽  
Mass Star ◽  
Distance Measurements ◽  
Spiral Arms ◽  
Long Baseline

The nature of the spiral structure of the Milky Way has long been debated. Only in the last decade have astronomers been able to accurately measure distances to a substantial number of high-mass star-forming regions, the classic tracers of spiral structure in galaxies. We report distance measurements at radio wavelengths using the Very Long Baseline Array for eight regions of massive star formation near the Local spiral arm of the Milky Way. Combined with previous measurements, these observations reveal that the Local Arm is larger than previously thought, and both its pitch angle and star formation rate are comparable to those of the Galaxy’s major spiral arms, such as Sagittarius and Perseus. Toward the constellation Cygnus, sources in the Local Arm extend for a great distance along our line of sight and roughly along the solar orbit. Because of this orientation, these sources cluster both on the sky and in velocity to form the complex and long enigmatic Cygnus X region. We also identify a spur that branches between the Local and Sagittarius spiral arms.

scholarly journals Dense gas in a giant molecular filament

2020 ◽  
Vol 641 ◽  
pp. A53 ◽  
Author(s):  
Y. Wang ◽  
H. Beuther ◽  
N. Schneider ◽  
S. E. Meidt ◽  
H. Linz ◽  
...  
Keyword(s):  
Star Formation ◽  
Power Law ◽  
Milky Way ◽  
Galactic Plane ◽  
High Mass ◽  
Mass Star ◽  
Evolutionary Trend ◽  
Dense Gas ◽  
Nearby Galaxies ◽  
Intensity Ratios

Context. Recent surveys of the Galactic plane in the dust continuum and CO emission lines reveal that large (≳50 pc) and massive (≳105 M⊙) filaments, know as giant molecular filaments (GMFs), may be linked to Galactic dynamics and trace the mid-plane of the gravitational potential in the Milky Way. Yet our physical understanding of GMFs is still poor. Aims. We investigate the dense gas properties of one GMF, with the ultimate goal of connecting these dense gas tracers with star formation processes in the GMF. Methods. We imaged one entire GMF located at l ~ 52–54° longitude, GMF54 (~68 pc long), in the empirical dense gas tracers using the HCN(1–0), HNC(1–0), and HCO+(1–0) lines, and their 13C isotopologue transitions, as well as the N2H+(1–0) line. We studied the dense gas distribution, the column density probability density functions (N-PDFs), and the line ratios within the GMF. Results. The dense gas molecular transitions follow the extended structure of the filament with area filling factors between 0.06 and 0.28 with respect to 13CO(1–0). We constructed the N-PDFs of H2 for each of the dense gas tracers based on their column densities and assumed uniform abundance. The N-PDFs of the dense gas tracers appear curved in log–log representation, and the HCO+ N-PDF has the flattest power-law slope index. Studying the N-PDFs for sub-regions of GMF54, we found an evolutionary trend in the N-PDFs that high-mass star-forming and photon-dominated regions have flatter power-law indices. The integrated intensity ratios of the molecular lines in GMF54 are comparable to those in nearby galaxies. In particular, the N2H+/13CO ratio, which traces the dense gas fraction, has similar values in GMF54 and all nearby galaxies except Ultraluminous Infrared Galaxies. Conclusions. As the largest coherent cold gaseous structure in our Milky Way, GMFs, are outstanding candidates for connecting studies of star formation on Galactic and extragalactic scales. By analyzing a complete map of the dense gas in a GMF we have found that: (1) the dense gas N-PDFs appear flatter in more evolved regions and steeper in younger regions, and (2) its integrated dense gas intensity ratios are similar to those of nearby galaxies.

scholarly journals Molecular Abundance Ratios as a Tracer of Accelerated Collapse in Regions of High‐Mass Star Formation

2005 ◽  
Vol 620 (2) ◽  
pp. 795-799 ◽  
Author(s):  
C. J. Lintott ◽  
S. Viti ◽  
J. M. C. Rawlings ◽  
D. A. Williams ◽  
T. W. Hartquist ◽  
...  
Keyword(s):  
Star Formation ◽  
High Mass ◽  
Mass Star

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 ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex

2017 ◽  
Vol 849 (1) ◽  
pp. 25 ◽  
Author(s):  
Tie Liu ◽  
John Lacy ◽  
Pak Shing Li ◽  
Ke Wang ◽  
Sheng-Li Qin ◽  
...  
Keyword(s):  
Star Formation ◽  
High Mass ◽  
Mass Star
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