Alma–imf

Nony, T.; Galván-Madrid, R.; Motte, F.; Pouteau, Y.; Cunningham, N.

doi:10.1051/0004-6361/202244762

“…These results suggest that the protostellar cores are more massive and denser than the prestellar cores, indicating a core mass growth from the prestellar to protostellar stages (e.g., Kong et al 2021;Takemura et al 2023;Nony et al 2023). In addition, Li et al (2020b) found that the more massive cores have a longer accretion history than the less massive cores.…”

Section: Core Mass Growthmentioning

confidence: 91%

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VIII. Dynamics of Embedded Dense Cores

Li

¹

,

Sanhueza

²

,

Zhang

³

et al. 2023

ApJ

View full text Add to dashboard Cite

We present dynamical properties of 294 cores embedded in twelve IRDCs observed as part of the ASHES Survey. Protostellar cores have higher gas masses, surface densities, column densities, and volume densities than prestellar cores, indicating core mass growth from the prestellar to the protostellar phase. We find that ∼80% of cores with virial parameter (α) measurements are gravitationally bound (α < 2). We also find an anticorrelation between the mass and the virial parameter of cores, with massive cores having on average lower virial parameters. Protostellar cores are more gravitationally bound than prestellar cores, with an average virial parameter of 1.2 and 1.5, respectively. The observed nonthermal velocity dispersion (from N2D+ or DCO+) is consistent with simulations in which turbulence is continuously injected, whereas the core-to-core velocity dispersion is neither in agreement with driven nor decaying turbulence simulations. We find a not significant increment in the line velocity dispersion from prestellar to protostellar cores, suggesting that the dense gas within the core traced by these deuterated molecules is not yet severely affected by turbulence injected from outflow activity at the early evolutionary stages traced in ASHES. The most massive cores are strongly self-gravitating and have greater surface density, Mach number, and velocity dispersion than cores with lower masses. Dense cores do not have significant velocity shifts relative to their low-density envelopes, suggesting that dense cores are comoving with their envelopes. We conclude that the observed core properties are more in line with the predictions of clump-fed scenarios rather than with those of core-fed scenarios.

show abstract

“…We conclude that any effect of spatial filtering on our measured flux densities is small, and adopt a flux-density uncertainty of 5% for all data sets. Nony et al (2023) In order to evaluate potential biases in our outflow identification methodology, we compare the outflows we identify in W43-MM2 and W43-MM3 with those identified by Nony et al (2023) for these same fields. Nony et al (2023) used both 12 CO (2-1) and SiO (5-4) line cubes to identify protostellar outflows by eye in W43-MM2 and W43-MM3.…”

Section: Flux Filtering On Large Spatial Scalesmentioning

confidence: 99%

“…Nony et al (2023) In order to evaluate potential biases in our outflow identification methodology, we compare the outflows we identify in W43-MM2 and W43-MM3 with those identified by Nony et al (2023) for these same fields. Nony et al (2023) used both 12 CO (2-1) and SiO (5-4) line cubes to identify protostellar outflows by eye in W43-MM2 and W43-MM3. They require emission of 5σ in three consecutive channels in the CO cube only in order to identify a candidate.…”

Section: Flux Filtering On Large Spatial Scalesmentioning

confidence: 99%

“…They require emission of 5σ in three consecutive channels in the CO cube only in order to identify a candidate. Nony et al (2023) centered their search on dust cores specifically, as their goal is to distinguish prestellar from protostellar cores through the presence of outflow emission.…”

Section: Flux Filtering On Large Spatial Scalesmentioning

confidence: 99%

“…In this paper, we analyze the SiO emission in these 15 protoclusters. In order to perform an unbiased search for SiO emission, we search the SiO images directly rather than starting from the locations of known continuum sources (Nony et al 2020(Nony et al , 2023. This large, homogeneous sample of outflow candidates will serve as a comprehensive resource for followup studies of the individual outflows and overall outflow populations in these fields.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

ALMA-IMF. IX. Catalog and Physical Properties of 315 SiO Outflow Candidates in 15 Massive Protoclusters

Towner,

Ginsburg,

Dell’Ova

et al. 2023

ApJ

Self Cite

4

0

View full text Add to dashboard Cite

We present a catalog of 315 protostellar outflow candidates detected in SiO J = 5 − 4 in the ALMA-IMF Large Program, observed with ∼2000 au spatial resolution, 0.339 km s−1 velocity resolution, and 2–12 mJy beam−1 (0.18–0.8 K) sensitivity. We find median outflow masses, momenta, and kinetic energies of ∼0.3 M ⊙, 4 M ⊙ km s−1, and 1045 erg, respectively. Median outflow lifetimes are 6000 yr, yielding median mass, momentum, and energy rates of M ̇ = 10−4.4 M ⊙ yr−1, P ̇ = 10−3.2 M ⊙ km s−1 yr−1, and E ̇ = 1 L ⊙. We analyze these outflow properties in the aggregate in each field. We find correlations between field-aggregated SiO outflow properties and total mass in cores (∼3σ–5σ), and no correlations above 3σ with clump mass, clump luminosity, or clump luminosity-to-mass ratio. We perform a linear regression analysis and find that the correlation between field-aggregated outflow mass and total clump mass—which has been previously described in the literature—may actually be mediated by the relationship between outflow mass and total mass in cores. We also find that the most massive SiO outflow in each field is typically responsible for only 15%–30% of the total outflow mass (60% upper limit). Our data agree well with the established mechanical force−bolometric luminosity relationship in the literature, and our data extend this relationship up to L ≥ 106 L ⊙ and P ̇ ≥ 1 M ⊙ km s−1 yr−1. Our lack of correlation with clump L/M is inconsistent with models of protocluster formation in which all protostars start forming at the same time.

show abstract

Alma-Imf

Pouteau¹,

Motte²,

T.³

et al. 2023

A&A

View full text Add to dashboard Cite

Context. Among the most central open questions regarding the initial mass function (IMF) of stars is the impact of environment on the shape of the core mass function (CMF) and thus potentially on the IMF. Aims. The ALMA-IMF Large Program aims to investigate the variations in the core distributions (CMF and mass segregation) with cloud characteristics, such as the density and kinematic of the gas, as diagnostic observables of the formation process and evolution of clouds. The present study focuses on the W43-MM2&MM3 mini-starburst, whose CMF has recently been found to be top-heavy with respect to the Salpeter slope of the canonical IMF. Methods. W43-MM2&MM3 is a useful test case for environmental studies because it harbors a rich cluster that contains a statistically significant number of cores (specifically, 205 cores), which was previously characterized in Paper III. We applied a multi-scale decomposition technique to the ALMA 1.3 mm and 3 mm continuum images of W43-MM2&MM3 to define six subregions, each 0.5–1 pc in size. For each subregion we characterized the probability distribution function of the high column density gas, η-PDF, using the 1.3 mm images. Using the core catalog, we investigate correlations between the CMF and cloud and core properties, such as the η-PDF and the core mass segregation. Results. We classify the W43-MM2&MM3 subregions into different stages of evolution, from quiescent to burst to post-burst, based on the surface number density of cores, number of outflows, and ultra-compact HII presence. The high-mass end (>1 M⊙) of the subregion CMFs varies from close to the Salpeter slope (quiescent) to top-heavy (burst and post-burst). Moreover, the second tail of the η-PDF varies from steep (quiescent) to flat (burst and post-burst), as observed for high-mass star-forming clouds. We find that subregions with flat second η-PDF tails display top-heavy CMFs. Conclusions. In dynamical environments such as W43-MM2&MM3, the high-mass end of the CMF appears to be rooted in the cloud structure, which is at high column density and surrounds cores. This connection stems from the fact that cores and their immediate surroundings are both determined and shaped by the cloud formation process, the current evolutionary state of the cloud, and, more broadly, the star formation history. The CMF may evolve from Salpeter to top-heavy throughout the star formation process from the quiescent to the burst phase. This scenario raises the question of if the CMF might revert again to Salpeter as the cloud approaches the end of its star formation stage, a hypothesis that remains to be tested.

show abstract

Alma–imf

Cited by 18 publications

References 67 publications

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VIII. Dynamics of Embedded Dense Cores

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VIII. Dynamics of Embedded Dense Cores

ALMA-IMF. IX. Catalog and Physical Properties of 315 SiO Outflow Candidates in 15 Massive Protoclusters

Alma-Imf

Contact Info

Product

Resources

About