scholarly journals RCW 36 in the Vela Molecular Ridge: Evidence for high-mass star-cluster formation triggered by cloud–cloud collision

2018 ◽  
Vol 70 (SP2) ◽  
Author(s):  
Hidetoshi Sano ◽  
Rei Enokiya ◽  
Katsuhiro Hayashi ◽  
Mitsuyoshi Yamagishi ◽  
Shun Saeki ◽  
...  
Keyword(s):  
Cluster Formation ◽  
Star Cluster ◽  
High Mass ◽  
Mass Star

scholarly journals Is there a fundamental upper limit to the mass of a star cluster?

2019 ◽  
Vol 488 (4) ◽  
pp. 5400-5408 ◽  
Author(s):  
Mark A Norris ◽  
Glenn van de Ven ◽  
Sheila J Kannappan ◽  
Eva Schinnerer ◽  
Ryan Leaman
Keyword(s):  
Cluster Formation ◽  
Star Clusters ◽  
Stellar Mass ◽  
Star Cluster ◽  
High Mass ◽  
Mass Star ◽  
Exact Nature ◽  
Turn Of The Millennium ◽  
Stellar Masses ◽  
Mass Dependent

Abstract The discovery around the turn of the millennium of a population of very massive (M⋆ > 2 × 106 M⊙) compact stellar systems (CSS) with physical properties (radius, velocity dispersion, stellar mass etc.) that are intermediate between those of the classical globular cluster (GC) population and galaxies led to questions about their exact nature. Recently a consensus has emerged that these objects, usually called ultracompact dwarfs (UCDs), are a mass-dependent mixture of high-mass star clusters and remnant nuclei of tidally disrupted galaxies. The existence of genuine star clusters with stellar masses >107 M⊙ naturally leads to questions about the upper mass limit of the star cluster formation process. In this work we compile a comprehensive catalogue of CSS, and reinforce the evidence that the true ancient star cluster population has a maximum mass of M⋆ ∼ 5 × 107 M⊙, corresponding to a stellar mass at birth of close to 108 M⊙. We then discuss several physical and statistical mechanisms potentially responsible for creating this limiting mass.

scholarly journals Cluster formation induced by a cloud–cloud collision in [DBS2003]179

2020 ◽  
Author(s):  
Sho Kuwahara ◽  
Kazufumi Torii ◽  
Norikazu Mizuno ◽  
Shinji Fujita ◽  
Mikito Kohno ◽  
...  
Keyword(s):  
Near Infrared ◽  
Cluster Formation ◽  
Dust Emission ◽  
Star Clusters ◽  
High Ratio ◽  
Star Cluster ◽  
High Mass ◽  
Mass Star ◽  
The Galaxy ◽  
Super Star Clusters

Abstract [DBS2003]179 is a super star cluster in the Galaxy discovered in deep near-infrared observations. We carried out CO $J$ = 1–0 and $J$ = 3–2 observations of the region of [DBS2003]179 with NANTEN2, ASTE, and the Mopra 22 m telescope. We identified and mapped two molecular clouds that are likely to be associated with the cluster. This association is supported by the spatial correlation with the corresponding 8$\, \mu$m Spitzer image and by a high ratio of the two transitions of $^{12}$CO($J$ = 3–2 and $J$ = 1–0). The two clouds show complementary distributions in space, and bridging features connect them in velocity. We hypothesize that the two clouds collided with each other 1–2 Myr ago and that the collision compressed the interfacial layer, triggering the formation of the cluster. This offers an additional piece of evidence for a super star cluster formed by a cloud–cloud collision, alongside the four super star clusters Westerlund$\:2$, NGC 3603, RCW 38, and R 136. These findings indicate that the known super star clusters with closely associated dust emission were formed by cloud–cloud collisions, lending support to the important role of cloud–cloud collisions in high-mass star formation.

Efficiencies of Low‐Mass Star and Star Cluster Formation

2000 ◽  
Vol 545 (1) ◽  
pp. 364-378 ◽  
Author(s):  
Christopher D. Matzner ◽  
Christopher F. McKee
Keyword(s):  
Cluster Formation ◽  
Star Cluster ◽  
Mass Star ◽  
Low Mass

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 Subsonic islands within a high-mass star-forming infrared dark cloud

2018 ◽  
Vol 611 ◽  
pp. L3 ◽  
Author(s):  
Vlas Sokolov ◽  
Ke Wang ◽  
Jaime E. Pineda ◽  
Paola Caselli ◽  
Jonathan D. Henshaw ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Cluster Formation ◽  
High Mass ◽  
Mass Star ◽  
Dark Cloud ◽  
Turbulent Dissipation ◽  
Very Large Array ◽  
Star Forming ◽  
Star Forming Regions ◽  
Mach Number Distribution

High-mass star forming regions are typically thought to be dominated by supersonic motions. We present combined Very Large Array and Green Bank Telescope (VLA+GBT) observations of NH3 (1,1) and (2,2) in the infrared dark cloud (IRDC) G035.39-00.33, tracing cold and dense gas down to scales of 0.07 pc. We find that, in contrast to previous, similar studies of IRDCs, more than a third of the fitted ammonia spectra show subsonic non-thermal motions (mean line width of 0.71 km s−1), and sonic Mach number distribution peaks around ℳ = 1. As possible observational and instrumental biases would only broaden the line profiles, our results provide strong upper limits to the actual value of ℳ, further strengthening our findings of narrow line widths. This finding calls for a re-evaluation of the role of turbulent dissipation and subsonic regions in massive-star and cluster formation. Based on our findings in G035.39, we further speculate that the coarser spectral resolution used in the previous VLA NH3 studies may have inhibited the detection of subsonic turbulence in IRDCs. The reduced turbulent support suggests that dynamically important magnetic fields of the 1 mG order would be required to support against possible gravitational collapse. Our results offer valuable input into the theories and simulations that aim to recreate the initial conditions of high-mass star and cluster formation.

scholarly journals G337.342–0.119 (The “Pebble”): A Cold, Dense, High-mass Molecular Cloud with Unusually Large Line Widths and a Candidate High-mass Star Cluster Progenitor

2018 ◽  
Vol 869 (2) ◽  
pp. 102 ◽  
Author(s):  
James M. Jackson ◽  
Yanett Contreras ◽  
Jill M. Rathborne ◽  
J. Scott Whitaker ◽  
Andrés Guzmán ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Star Cluster ◽  
High Mass ◽  
Mass Star ◽  
Line Widths

scholarly journals Young star cluster populations in the E-MOSAICS simulations

2019 ◽  
Vol 490 (2) ◽  
pp. 1714-1733 ◽  
Author(s):  
Joel Pfeffer ◽  
Nate Bastian ◽  
J M Diederik Kruijssen ◽  
Marta Reina-Campos ◽  
Robert A Crain ◽  
...  
Keyword(s):  
High Redshift ◽  
Cluster Formation ◽  
Formation Rate ◽  
Mass Function ◽  
Young Star ◽  
Star Cluster ◽  
High Mass ◽  
Cluster Mass ◽  
Test Models ◽  
Hydrodynamical Simulations

ABSTRACT We present an analysis of young star clusters (YSCs) that form in the E-MOSAICS cosmological, hydrodynamical simulations of galaxies and their star cluster populations. Through comparisons with observed YSC populations, this work aims to test models for YSC formation and obtain an insight into the formation processes at work in part of the local galaxy population. We find that the models used in E-MOSAICS for the cluster formation efficiency and high-mass truncation of the initial cluster mass function ($M_\rm {c,\ast }$) both quantitatively reproduce the observed values of cluster populations in nearby galaxies. At higher redshifts (z ≥ 2, near the peak of globular cluster formation) we find that, at a constant star formation rate (SFR) surface density, $M_\rm {c,\ast }$ is larger than at z = 0 by a factor of four due to the higher gas fractions in the simulated high-redshift galaxies. Similar processes should be at work in local galaxies, offering a new way to test the models. We find that cluster age distributions may be sensitive to variations in the cluster formation rate (but not SFR) with time, which may significantly affect their use in tests of cluster mass-loss. By comparing simulations with different implementations of cluster formation physics, we find that (even partially) environmentally independent cluster formation is inconsistent with the brightest cluster-SFR and specific luminosity-$\Sigma _\rm {SFR}$ relations, whereas these observables are reproduced by the fiducial, environmentally varying model. This shows that models in which a constant fraction of stars form in clusters are inconsistent with observations.

scholarly journals Comparison of Low-Mass and High-Mass Star Formation

2015 ◽  
Vol 11 (S315) ◽  
pp. 154-162 ◽  
Author(s):  
Jonathan C. Tan
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Initial Conditions ◽  
Cluster Formation ◽  
Theoretical Models ◽  
High Mass ◽  
Mass Star ◽  
Massive Star Formation ◽  
Low Mass ◽  
Core Accretion

AbstractI review theoretical models of star formation and how they apply across the stellar mass spectrum. Several distinct theories are under active study for massive star formation, especiallyTurbulent Core Accretion,Competitive AccretionandProtostellar Mergers, leading to distinct observational predictions. These include the types of initial conditions, the structure of infall envelopes, disks and outflows, and the relation of massive star formation to star cluster formation. Even for Core Accretion models, there are several major uncertainties related to the timescale of collapse, the relative importance of different processes for preventing fragmentation in massive cores, and the nature of disks and outflows. I end by discussing some recent observational results that are helping to improve our understanding of these processes.

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