J/ApJ/949/46 High-mass starless clumps from ATLASGAL & SEDIGISM (Huang+, 2023)
High-mass starless clumps: dynamical state and correlation between physical
parameters.
Huang Bo, Wang Ke, Girart J.M., Jiao W., He Q., Liang E.
<Astrophys. J., 949, 46 (2023)>
=2023ApJ...949...46H 2023ApJ...949...46H
ADC_Keywords: Interstellar medium; Carbon monoxide; Surveys; Magnetic fields;
Molecular clouds; Space velocities; Velocity dispersion;
Galactic plane
Keywords: Molecular clouds ; Interstellar medium ; Star formation ;
Interstellar dynamics ; Interstellar magnetic fields
Abstract:
In order to study the initial conditions of massive star formation, we
have previously built a sample of 463 high-mass starless clumps
(HMSCs) across the inner Galactic plane covered by multiple continuum
surveys. Here, we use 13CO(2-1) line data from the SEDIGISM survey,
which covers 78° in longitude (-60°<l<18°, |b|<0.5°)
with 30" resolution, to investigate the global dynamical state of
these parsec-scale HMSCs (207 sources with good-quality data, mass
102-105M☉, size 0.1-3.6pc). We find that most HMSCs are
highly turbulent with a median Mach number MS∼8.2, and 44%-55% of
them are gravitationally bound (with virial parameter αvir≲2)
if no magnetic fields are present. A median magnetic field strength of
0.33-0.37mG would be needed to support these bound clumps against
collapse, in agreement with previous observations of magnetic fields
in regions of massive star formation. Luminosity-to-mass ratio, an
important tracer of evolutionary stage, is strongly correlated with
dust temperature. Magnetic field strength is also correlated with
density. The Larson line width-size scaling does not hold in HMSCs.
This study advances our understanding of the global properties of
HMSCs, and our high-resolution observations with the Atacama Large
Millimeter/submillimeter Array are in progress to study the resolved
properties.
Description:
The structure, excitation, and dynamics of the inner Galactic
interstellar medium (SEDIGISM) survey (Schuller+ 2017, J/A+A/601/A124
and 2021, J/MNRAS/500/3064; Duarte-Cabral+ 2021, J/MNRAS/500/3027)
covers 78° of longitude of the inner Galaxy (-60°<l<18°,
|b|<0.5°) with a 30" resolution in 13CO(2-1) and C18O(2-1)
rotational transitions.
We use the 13CO(2-1) emission line data at the position of all the
identified high-mass starless clump (HMSC) sources reported by Y17
(Yuan+ 2017, J/ApJS/231/11).
Following Y17, we have presented an analysis focusing on the global
dynamical properties of a representative sample of 207 HMSCs by
cross-matching the SEDIGISM and the APEX Telescope Large Area Survey
of the Galaxy (ATLASGAL; 2009A&A...504..415S 2009A&A...504..415S) surveys and removing
sources associated with outflows.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 85 207 Physical parameters of the 207 high-mass starless
clump (HMSC) candidates
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See also:
J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)
J/A+A/481/345 : SED evolution in massive YSOs (Molinari+, 2008)
J/A+A/540/A113 : Starless clumps in ATLASGAL (Tackenberg+, 2012)
J/A+A/544/A146 : ATLASGAL cold high-mass clumps with NH3 (Wienen+, 2012)
J/ApJS/209/2 : The BGPS. X. Dense molecular gas (Shirley+, 2013)
J/A+A/565/A75 : ATLASGAL: dust condensations in Gal. plane (Csengeri+, 2014)
J/MNRAS/451/3089 : Young clumps embedded in IRDC (Traficante+, 2015)
J/ApJ/822/59 : BGPS. XIV. Molecular cloud clumps GBT obs. (Svoboda+, 2016)
J/MNRAS/471/100 : Hi-GAL compact source catalog. -71.0<l<67.0 (Elia+, 2017)
J/ApJ/846/144 : Virial analysis of the dense cores in Orion A (Kirk+, 2017)
J/A+A/601/A124 : Clouds in SEDIGISM field (Schuller+, 2017)
J/ApJS/231/11 : High-mass starless clump cand. from ATLASGAL (Yuan+, 2017)
J/MNRAS/477/2220 : Larson relations in massive clumps (Traficante+, 2018)
J/MNRAS/473/1059 : Complete sample of Gal. clump properties (Urquhart+, 2018)
J/MNRAS/500/3027 : The SEDIGISM survey: molecular clouds (Duarte-Cabral+, 2021)
J/MNRAS/500/3064 : The SEDIGISM survey: First Data Release (Schuller+, 2021)
J/A+A/658/A160 : SEDIGISM survey, search for molecular outflows (Yang+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Source Name (GLLL.llll+B.bbbb)
18- 24 F7.2 km/s VLSR [-118/152] Centroid velocity
26- 29 F4.2 km/s e_VLSR [0.01/1] Uncertainty in VLSR
31- 35 F5.2 km/s DV [0.9/34.6] Line width
37- 40 F4.2 km/s e_DV [0.03/4.8] Uncertainty in DV
42- 46 F5.2 km/s sigma-v [0.37/14.7] Total velocity dispersion
48- 51 F4.2 km/s sigma-th [0.05/0.1] Thermal term velocity dispersion
53- 58 F6.3 km/s sigma-nth [0.36/14.7] Non-thermal term velocity
dispersion
60- 64 F5.2 --- M [1.74/62.1] Mach number
66- 73 E8.1 Msun Mvir [87/410000] Virial mass
75- 80 F6.2 --- aVir [0.04/161.1] Virial parameter, αvir
82- 85 F4.2 mG B [0.08/2.9]? Required B-field to support
against the collapse
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 26-May-2025