The role of collision speed, cloud density, and turbulence in the formation of young massive clusters via cloud–cloud collisions

Liow, Kong You; Dobbs, Clare

doi:10.1093/mnras/staa2857

Cited by 32 publications

(10 citation statements)

References 84 publications

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“…time) increases, especially as they approach 10 4 M . Similar behaviour is seen by Liow & Dobbs (2020) in models of cloud-cloud collisions which do not include feedback, where massive clusters contract once gravity becomes important. The results imply that variations in metallicity, dust absorption, and radiation pressure do not guarantee changes in cluster compactness, even though the H regions produced by each model are of different sizes and masses (as shown in Fig.…”

Section: Star Formationsupporting

confidence: 73%

The growth of H II regions around massive stars: the role of metallicity and dust

Ali

2021

Preprint

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Gas metallicity 𝑍 and the related dust-to-gas ratio 𝑓 d can influence the growth of H regions via metal line cooling and UV absorption. We model these effects in star-forming regions containing massive stars. We compute stellar feedback from photoionization and radiation pressure (RP) using Monte Carlo radiative transfer coupled with hydrodynamics, including stellar and diffuse radiation fields. We follow a 10 5 M turbulent cloud with 𝑍/Z = 2, 1, 0.5, 0.1 and 𝑓 d = 0.01𝑍/Z with a cluster-sink particle method for star formation. The models evolve for at least 1.5 Myr under feedback. Lower 𝑍 results in higher temperatures and therefore larger H regions. For 𝑍 Z , radiation pressure 𝑃 rad can dominate locally over the gas pressure 𝑃 gas in the inner half-parsec around sink particles. Globally, the ratio of 𝑃 rad /𝑃 gas is around 1 (2 Z ), 0.3 (Z ), 0.1 (0.5 Z ), and 0.03 (0.1 Z ). In the solar model, excluding RP results in an ionized volume several times smaller than the fiducial model with both mechanisms. Excluding RP and UV attenuation by dust results in a larger ionized volume than the fiducial case. That is, UV absorption hinders growth more than RP helps it. The radial expansion velocity of ionized gas reaches +15 km s −1 outwards, while neutral gas has inward velocities for most of the runtime, except for 0.1 Z which exceeds +4 km s −1 . 𝑍 and 𝑓 d do not significantly alter the star formation efficiency, rate, or cluster half-mass radius, with the exception of 0.1 Z due to the earlier expulsion of neutral gas.

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Section: Star Formationsupporting

confidence: 73%

The growth of H II regions around massive stars: the role of metallicity and dust

Ali

2021

Preprint

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“…They reported the dependencies in column density for the formation of O-type stars in isolation and/or in a cluster. They suggested that 10 O stars (or a single O star) can be produced for total column density of 10 23 (10 22 ) cm −2 (see also Inoue et al 2018;Liow & Dobbs 2020).…”

Section: Discussionmentioning

confidence: 99%

New evidences in IRDC G333.73+0.37: colliding filamentary clouds, hub-filament system, and embedded cores

Dewangan

2022

Preprint

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To unravel the star formation process, we present a multi-scale and multi-wavelength study of the filamentary infrared dark cloud (IRDC) G333.73+0.37, which hosts previously known two H regions located at its center. Each H region is associated with a mid-infrared source, and is excited by a massive OB star. Two filamentary structures and a hub-filament system (HFS) associated with one H region are investigated in absorption using the Spitzer 8.0 m image. The 13 CO(J = 2-1) and C 18 O(J = 2-1) line data reveal two velocity components (around −35.5 and −33.5 km s −1 ) toward the IRDC, favouring the presence of two filamentary clouds at different velocities. Nonthermal (or turbulent) motions are depicted in the IRDC using the C 18 O line data. The spatial distribution of young stellar objects (YSOs) identified using the VVV near-infrared data traces star formation activities in the IRDC. Low-mass cores are identified toward both the H regions using the ALMA 1.38 mm continuum map. The VLT/NACO adaptive-optics L ′ -band images show the presence of at least three point-like sources and the absence of small-scale features in the inner 4000 AU around YSOs NIR31 and MIR 16 located toward the H regions. The H regions and groups of YSO are observed toward the central part of the IRDC, where the two filamentary clouds intersect. A scenario of cloud-cloud collision or converging flows in the IRDC seems to be applicable, which may explain star formation activities including HFS and massive stars.

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“…We use the DBSCAN algorithm (Density-Based Spatial Clustering of Applications with Noise; Ester et al 1996) -see e.g. Joncour et al (2018) for a comprehensive description of the method and its usage for observed stellar systems, and Liow & Dobbs (2020) for an application in simulations of cloud-cloud collisions. We set 5 as the minimum number of members required to define a cluster, and 𝜖 = 3 pc as the maximum neighbour separation.…”

Section: Sink Clusteringmentioning

confidence: 99%

Stellar winds and photoionization in a spiral arm

Ali,

Bending,

Dobbs

2022

Preprint

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The role of different stellar feedback mechanisms in giant molecular clouds is not well understood. This is especially true for regions with many interacting clouds as would be found in a galactic spiral arm. In this paper, building on previous work by Bending et al., we extract a 500 × 500 × 100 pc section of a spiral arm from a galaxy simulation. We use smoothed particle hydrodynamics (SPH) to re-simulate the region at higher resolution (1 M per particle). We present a method for momentumdriven stellar winds from main sequence massive stars, and include this with photoionization, self-gravity, a galactic potential, and ISM heating/cooling. We also include cluster-sink particles with accretion radii of 0.78 pc to track star/cluster formation. The feedback methods are as robust as previous models on individual cloud scales (e.g. Dale et al.). We find that photoionization dominates the disruption of the spiral arm section, with stellar winds only producing small cavities (at most ∼ 30 pc). Stellar winds do not affect the resulting cloud statistics or the integrated star formation rate/efficiency, unlike ionization, which produces more stars, and more clouds of higher density and higher velocity dispersion compared to the control run without feedback. Winds do affect the sink properties, distributing star formation over more low-mass sinks (∼10 2 M ) and producing fewer high-mass sinks (∼10 3 M ). Overall, stellar winds play at best a secondary role compared to photoionization, and on many measures, they have a negligible impact.

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The role of collision speed, cloud density, and turbulence in the formation of young massive clusters via cloud–cloud collisions

Cited by 32 publications

References 84 publications

The growth of H II regions around massive stars: the role of metallicity and dust

The growth of H II regions around massive stars: the role of metallicity and dust

New evidences in IRDC G333.73+0.37: colliding filamentary clouds, hub-filament system, and embedded cores

Stellar winds and photoionization in a spiral arm

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