Infall Signatures in a Prestellar Core Embedded in the High-mass 70 μm Dark IRDC G331.372-00.116

Contreras, Y.; Sanhueza, Patricio; Jackson, James M.; Guzmán, Andrés E.; Longmore, Steven N.; Garay, Guido; Zhang, Qizhou; Nguyen-Luong, Q.; Tatematsu, Ken’ichi; Nakamura, Fúmitaka; Sakai, Takeshi; Ohashi, Satoshi; Liu, Tie; Saito, Masao; Gómez, Laura; Rathborne, Jill; Whitaker, S. P.

doi:10.3847/1538-4357/aac2ec

Cited by 82 publications

(101 citation statements)

References 53 publications

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“…To reproduce it requires a more sophisticated modeling, which is beyond the scope of this work. From the derived values of the infall speed (1.6 km s −1 ), core radius (0.03 pc), molecular weight µ H 2 (2.8), and molecular hydrogen density (1.5×10 7 cm −3 ) we estimate a mass infall rateṀ (=4π R 2 n(H 2 )µ H 2 m H v in ) of 1.9×10 −2 M /yr, value similar to those reported in other high-mass star forming regions (eg., Garay et al 2002;Beuther et al 2002;Contreras et al 2018 The observed radial intensity profile of the massive core, shown in Figure 21, deviates significantly from a Gaussian profile but is well approximated with a Plummer-like radial intensity profile of the form,…”

Section: The Massive Core At the Center Of The Protostellar Clumpmentioning

confidence: 90%

“…Our observations with spatial resolution of ∼0.03 pc, ten times smaller than that of Csengeri et al (2017), show that the number of cores per clump increases to 10, suggesting that we are resolving further fragmentation within MDCs. Recent studies of clumps with similar characteristics to those observed by Csengeri et al (2017) have reported levels of fragmentation ranging from 5 to 20 cores when observed at scales of 0.03-0.05 pc (eg., Lu et al 2018;Contreras et al 2018). Figure 19 shows the normalized cumulative distribution function (CDF), also known as empirical cumulative distribution function (eCDF).…”

Section: Mass Distributionmentioning

confidence: 99%

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ALMA Observations of Two Massive and Dense MALT90 Clumps

Neupane

Garay

Contreras

et al. 2020

ApJ

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We report Atacama Large Millimeter Array observations of 3 mm dust continuum emission and line emission, in HCO + , H 13 CO + , N 2 H + and CH 3 CN, towards two massive and dense clumps (MDCs) in early but distinct evolutionary phases (prestellar and protostellar), made with the goal of investigating their fragmentation characteristics at angular scales of ∼1 . Towards the prestellar clump we detected ten compact structures (cores), with radius from 1200 to 4500 AU and masses from 1.6 to 20 M . Half of these cores exhibit inverse P Cygni profiles in HCO + and are subvirialized indicating that they are undergoing collapse. Towards the protostellar clump we detected a massive (119 M ) central core, with a strong mass infall rate, and nine less massive cores, with masses from 1.7 to 27 M and radius from 1000 to 4300 AU. CH 3 CN rotational tem-Corresponding author: S., Neupane

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Section: The Massive Core At the Center Of The Protostellar Clumpmentioning

confidence: 90%

Section: Mass Distributionmentioning

confidence: 99%

ALMA Observations of Two Massive and Dense MALT90 Clumps

Neupane

Garay

Contreras

et al. 2020

ApJ

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“…High-mass prestellar cores, defined here as cores with masses >30 M , are the cornerstone of the turbulent core accretion model (McKee & Tan 2003;Tan et al 2013Tan et al , 2014. However, they have not been unambiguously found in IRDCs (Zhang et al 2009Wang et al 2014;Ohashi et al 2016;Sanhueza et al 2017;Contreras et al 2018;Beuther et al 2018a;Kong et al 2018b). The case is different in more evolved high-mass star-forming regions.…”

Section: High-mass Star Formation Picturementioning

confidence: 99%

“…The early fragmentation in 70 µm dark-IRDCs results in a power law index slightly shallower than Salpeter. The most massive cores can accrete material, growing in mass quite quickly according to the recent finding of Contreras et al (2018). They determine an accretion rate of 2 × 10 −3 M yr −1 in a relatively massive prestellar core.…”

Section: Core Mass Functionmentioning

confidence: 99%

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation

Sanhueza

Contreras

et al. 2019

ApJ

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168

278

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The ALMA Survey of 70 µm dark High-mass clumps in Early Stages (ASHES) has been designed to systematically characterize the earliest stages and to constrain theories of high-mass star formation. A deep understanding of highmass star formation requires the study of the clustered mode, which is the most commonly found in nature. A total of 12 massive (>500 M ), cold (≤15 K), 3.6-70 µm dark prestellar clump candidates, embedded in infrared dark clouds (IRDCs), were carefully selected in the pilot survey to be observed with the Atacama Large Millimeter/sub-millimeter Array (ALMA). Exploiting the unique capabilities of ALMA, we have mosaiced each clump (∼1 arcmin 2 ) in dust continuum and line emission with the 12 m, 7 m, and Total Power arrays at 224 GHz (1.34 mm), resulting in ∼1. 2 angular resolution (∼4800 AU at the average source distance of 4 kpc). As the first paper of the series, we concentrate on the dust continuum emission to reveal the clump fragmentation. We have detected a total of 294 cores, from which 84 (29%) are categorized as protostellar based on outflow activity or "warm core" line emission. The remaining 210 (71%) are considered prestellar core candidates. The number of detected cores is independent of the mass sensitivity range of the observations and, on average, more massive clumps tend to form more cores. We find no correlation between the mass of the host clump and the most massive embedded core. We find a large population of low-mass (<1 M ) cores and no high-mass (>30 M ) prestellar cores. The most massive prestellar core has a mass of 11 M . From the prestellar core mass function, we derive a power law index of 1.17 ± 0.10, slightly shallower than the Salpeter index of 1.35. We have used the minimum spanning tree technique to characterize the separation between cores and their spatial distribution, and to derive mass segregation ratios. While there is a range of core masses and core separations detected in the sample, the mean separation and mean mass of cores per clump are well explained

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“…It can be explained, however, by the presence of at least one undetected heavily embedded (proto)star(s). For example, recent studies by Liu et al (2018b) using single-dish telescopes and Contreras et al (2018) using the Atacama Large Millimeter/submillimeter Array (ALMA) detected high accretion rates in massive quiescent cores, which are com- Table 3 for each of the three epochs (left to right). The images have been re-scaled by the relative calibration process described in Section 3.…”

Section: Variable Candidate Found In This Studymentioning

confidence: 99%

Submillimeter Continuum Variability in Planck Galactic Cold Clumps

Park

Kim

Johnstone

et al. 2019

ApJS

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In the early stages of star formation, a protostar is deeply embedded in an optically thick envelope such that it is not directly observable. Variations in the protostellar accretion rate, however, will cause luminosity changes that are reprocessed by the surrounding envelope and are observable at submillimeter wavelengths. We searched for submillimeter flux variability toward 12 Planck Galactic Cold Clumps detected by the James Clerk Maxwell Telescope (JCMT)-SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE) survey. These observations were conducted at 850 µm using the JCMT/SCUBA-2. Each field was observed three times over about 14 months between 2016 April and 2017 June. We applied a relative flux calibration and achieved a calibration uncertainty of ∼ 3.6% on average. We identified 136 clumps across 12 fields and detected four sources with flux variations of ∼ 30%. For three of these sources, the variations appear to be primarily due to large-scale contamination, leaving one plausible candidate. The flux change of the candidate may be associated with low-or intermediate-mass star formation assuming a distance of 1.5 kpc, although we cannot completely rule out the possibility that it is a random deviation. Further studies with dedicated monitoring would provide a better understanding of the detailed relationship between submillimeter flux and accretion rate variabilities while enhancing the search for variability in star-forming clumps farther away than the Gould Belt.

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Infall Signatures in a Prestellar Core Embedded in the High-mass 70 μm Dark IRDC G331.372-00.116

Cited by 82 publications

References 53 publications

ALMA Observations of Two Massive and Dense MALT90 Clumps

ALMA Observations of Two Massive and Dense MALT90 Clumps

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation

Submillimeter Continuum Variability in Planck Galactic Cold Clumps

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