J/ApJ/950/148 ASHES. IX. Massive clumps with ALMA observations (Morii+, 2023)
The ALMA Survey of 70um dark High-mass clumps in Early Stages (ASHES).
IX. Physical properties and spatial distribution of cores in IRDCs.
Morii K., Sanhueza P., Nakamura F., Zhang Q., Sabatini G., Beuther H.,
Lu X., Li S., Garay G., Jackson J.M., Olguin F.A., Tafoya D.,
Tatematsu K., Izumi N., Sakai T., Silva A.
<Astrophys. J., 950, 148 (2023)>
=2023ApJ...950..148M 2023ApJ...950..148M
ADC_Keywords: Star Forming Region; Millimetric/submm sources;
Velocity dispersion; Interferometry
Keywords: Infrared dark clouds ; Star formation ; Star forming regions ;
Protoclusters ; Protostars
Abstract:
The initial conditions found in infrared dark clouds (IRDCs) provide
insights on how high-mass stars and stellar clusters form. We have
conducted high-angular resolution and high-sensitivity observations
toward thirty-nine massive IRDC clumps, which have been mosaicked
using the 12 and 7m arrays from the Atacama Large Millimeter/submillimeter
Array. The targets are 70µm dark massive (220-4900M☉), dense
(>104cm-3), and cold (∼10-20K) clumps located at distances between
2 and 6kpc. We identify an unprecedented number of 839 cores, with
masses between 0.05 and 81M☉ using 1.3mm dust continuum
emission. About 55% of the cores are low-mass (<1M☉), whereas
≲1% (7/839) are high-mass (≳27M☉). We detect no high-mass
prestellar cores. The most massive cores (MMC) identified within
individual clumps lack sufficient mass to form high-mass stars without
additional mass feeding. We find that the mass of the MMCs is
correlated with the clump surface density, implying denser clumps
produce more massive cores. There is no significant mass segregation
except for a few tentative detections. In contrast, most clumps show
segregation once the clump density is considered instead of mass.
Although the dust continuum emission resolves clumps in a network of
filaments, some of which consist of hub-filament systems, the majority
of the MMCs are not found in the hubs. Our analysis shows that
high-mass cores and MMCs have no preferred location with respect to
low-mass cores at the earliest stages of high-mass star formation.
Description:
Observations of the 39 ASHES clumps were carried out with ALMA in
Band 6 (∼224GHz; ∼1.34mm). The data were acquired through three
cycles: Cycle 3 (2015.1.01539.S, PI: P. Sanhueza), Cycle 5
(2017.1.00716.S, PI: P. Sanhueza), and Cycle 6 (2018.1.00192.S,
PI: P. Sanhueza).
We have conducted ALMA observations that resolve the whole clumps,
mosaicked with ten and three pointing by the 12 and 7m arrays,
respectively, at a final angular resolution of ∼1.2".
See Section 3.
We identified cores using the obtained 1.3mm continuum images.
In this paper, following the definitions of
Sanhueza+ (2019, J/ApJ/886/102), we use the term "core" to describe a
compact, dense object within a clump with a size of ∼0.01-0.1pc, a
mass of ∼10-1-102M☉, and a volume density of ∼105cm-3
that will likely form a single star or a small multiple system.
See Section 4.2.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 79 39 Physical properties of ASHES clumps
table2.dat 78 39 Observational parameters and information of
continuum images
table3.dat 73 839 Core properties obtained from dendrogram
table4.dat 60 839 Core physical parameters
table5.dat 43 39 Properties of cores in each clump
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See also:
J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)
J/ApJ/646/1009 : Structures of dust in Perseus molecular cloud (Kirk+, 2006)
J/ApJ/641/389 : Millimetric observations of IRDC cores (Rathborne+, 2006)
J/A+A/487/993 : MAMBO Mapping of c2d Clouds and Cores (Kauffmann+, 2008)
J/ApJS/197/25 : MALT90 pilot survey (Foster+, 2011)
J/ApJ/756/60 : A 3mm line survey in 37 IR dark clouds (Sanhueza+, 2012)
J/A+A/553/A115 : Millimetric and far-IR maps of IRDC 18310-4 (Beuther+, 2013)
J/A+A/561/A83 : SDC13 infrared dark clouds spectra (Peretto+, 2014)
J/MNRAS/443/1555 : ATLASGAL massive star forming clumps (Urquhart+, 2014)
J/A+A/581/A119 : Starless gas clump IRDC 18310-4 images (Beuther+, 2015)
J/ApJ/815/130 : High-mass molecular clumps from MALT90 (Guzman+, 2015)
J/MNRAS/450/1926 : Infall motions in massive star-forming regions (He+, 2015)
J/MNRAS/451/3089 : Young clumps embedded in IRDC (Traficante+, 2015)
J/A+A/600/L10 : Massive cluster progenitors from ATLASGAL (Csengeri+, 2017)
J/AJ/154/140 : MALT90 kinematic dist. to molecular clumps (Whitaker+, 2017)
J/ApJS/237/27 : Radio Ammonia Mid-plane Survey pilot survey (Hogge+, 2018)
J/ApJ/862/105 : Core mass function across Gal. env. II. IRDCs (Liu+, 2018)
J/MNRAS/473/1059 : Complete sample of Gal. clump properties (Urquhart+, 2018)
J/A+A/613/A11 : SDC13 NH3(1,1) and NH3(2,2) datacubes (Williams+, 2018)
J/A+A/622/A99 : Starless MDCs of NGC6334 molecular spectra (Louvet+, 2019)
J/ApJ/886/102 : ALMA obs. of 70um dark high-mass clumps (Sanhueza+, 2019)
J/A+A/635/A34 : Dense cores in Orion B from Herschel (Konyves+, 2020)
J/A+A/642/A87 : Hub-filament candidates (Kumar+, 2020)
J/A+A/635/A2 : NGC6334 ALMA 87.6GHz cont. emission map (Sadaghiani+, 2020)
J/MNRAS/503/4601 : ALMA-IRDC from cloud to core scales (Barnes+, 2021)
J/A+A/645/A94 : NGC 2264 clumps column densities (Nony+, 2021)
J/A+A/664/A26 : W43-MM2&MM3 ministarburst ALMA data (Pouteau+, 2022)
J/ApJ/936/80 : ASHES. VI. Core-Scale CO Depletion (Sabatini+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Clump Clump ATLASGAL catalog name (G1)
17- 18 I2 h RAh [13/18] Hour of Right Ascension (ICRS)
20- 21 I2 min RAm Minute of Right Ascension (ICRS)
23- 27 F5.2 s RAs Second of Right Ascension (ICRS)
29 A1 --- DE- Sign of the Declination (ICRS)
30- 31 I2 deg DEd Degree of Declination (ICRS)
33- 34 I2 arcmin DEm Arcminute of Declination (ICRS)
36- 39 F4.1 arcsec DEs Arcsecond of Declination (ICRS)
41- 43 F3.1 km/s dV [0.9/2.8] Observed velocity dispersion (1)
45- 47 F3.1 kpc Dist [2.4/6.1] Distance from the Sun (2)
49- 52 F4.1 K Tcl [10.3/21.2] Clump dust temperature (3)
54- 58 I5 Msun Mref [423/15276] Reference mass (4)
60- 63 F4.2 pc Rcl [0.24/0.76] Clump radius (5)
65- 68 I4 Msun Mcl [200/4900] Clump mass (5)
70- 73 F4.2 g.cm-2 Sigmacl [0.12/1.11] Clump surface density (5)
75- 79 F5.2 10+4cm-3 nH2 [1/13.3] Clump molecular volume density (5)
--------------------------------------------------------------------------------
Note (1): Observed velocity dispersion, which was obtained by the
fitting of the line profile of C18O (J=2-1) averaged within the
clump with a 1-d Gaussian, which was observed by Total Power (TP).
Note (2): The distance from the Sun (5) is from Whitaker+ 2017, J/AJ/154/140
Note (3): Dust temperature is from Guzman+ 2015, J/ApJ/815/130
Note (4): Reference mass is cited from Traficante+ 2015, J/MNRAS/451/3089
and Contreras+ 2017MNRAS.466..340C 2017MNRAS.466..340C for clumps in the 1st and 4th quadrant,
respectively.
Note (5): Properties are fitting results of 2-d Gaussian for 870um
continuum images.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Clump Clump ATLASGAL catalog name (G1)
18- 24 A7 m Base Baselines, in meters
26- 40 A15 --- Config Configurations
42- 56 A15 --- Antennas Number (or range) of antennas (1)
58- 61 F4.2 arcsec Maj [1.24/1.52] Beam Size, major axis
63- 66 F4.2 arcsec Min [0.8/1.3] Beam Size, minor axis
68- 70 F3.1 --- Ratio [1.1/6.1] Flux ratio, F12m + F7m / F12m,
Section 4.1
72- 73 I2 % Frecov [7/45] Recoverable fraction, ALMA to
Single dish, Section 4.1
75- 78 F4.2 mJy/beam RMS [0.07/0.2] Continuum sensitivity, RMS Noise
--------------------------------------------------------------------------------
Note (1): The number (or range) of antennas of 7m are shown within
parenthesis.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [0/838] Sequential identifier
5- 19 A15 --- Clump Clump ATLASGAL catalog name (G1)
21- 26 A6 --- Core Core name (Unique within Clump)
28- 29 I2 h RAh [13/18] Hour of Right Ascension (ICRS)
31- 32 I2 min RAm Minute of Right Ascension (ICRS)
34- 38 F5.2 s RAs Second of Right Ascension (ICRS)
40 A1 --- DE- Sign of the Declination (ICRS)
41- 42 I2 deg DEd Degree of Declination (ICRS)
44- 45 I2 arcmin DEm Arcminute of Declination (ICRS)
47- 51 F5.2 arcsec DEs Arcsecond of Declination (ICRS)
53- 56 F4.2 arcsec maj [0.67/7.14] Major axis of cores (FWHM)
58- 61 F4.2 arcsec min [0.36/4.23] Minor axis of cores (FWHM)
63- 67 F5.2 mJy/beam Fpeak [0.26/40.8] Peak intensity
69- 73 F5.2 mJy Fint [0.25/67.5] Flux Density
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 -- Seq [0/838] Sequential identifier
5- 19 A15 -- Clump Clump ATLASGAL catalog name (G1)
21- 26 A6 -- Core Core name (Unique within Clump)
28- 31 F4.1 K Tdust [6.5/22.8] Dust temperature used for mass
calculation
33- 37 F5.2 Msun Mcore [0.05/81.1] Core mass
39- 43 F5.2 10+23cm-2 NH2pk [0.07/18.4] Column density at continuum peak
in a unit of 1023cm-2
45- 49 I5 au Rad [830/10930] Core radius, the geometric mean
of the FWHM divided by 2.
51- 54 F4.2 g.cm-2 Sigma [0.05/9.7] Surface density
56- 60 F5.2 10+6cm-3 nH2 [0.1/29] Molecular volume density
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Clump Clump ATLASGAL catalog name (G1)
17- 18 I2 --- Ncore [8/39] Total number of cores identified in
each clump
20- 23 F4.1 Msun Mmax [1.7/81.1] Maximum core mass
25- 28 F4.2 Msun Mmed [0.2/3.83] Median core mass
30- 33 F4.2 Msun Mmin [0.05/1.31] Minimum core mass
35- 38 F4.2 Msun M3.5sig [0.05/0.6] Mass sensitivity in each clump (1)
40- 43 F4.1 % CFE [0.6/16.4] Core formation efficiency (2)
--------------------------------------------------------------------------------
Note (1): Mass when F1.3mm is 3.5σ.
Note (2): Ratio of total core mass to clump mass.
--------------------------------------------------------------------------------
Global notes:
Note (G1): By replacing G for AGAL, the source name Column (1) matches
with the ATLASGAL simple names, Schuller+ 2009A&A...504..415S 2009A&A...504..415S;
Urquhart+ (2014, J/MNRAS/443/1555; 2018, J/MNRAS/473/1059).
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History:
From electronic version of the journal
References:
Sanhueza et al. Paper I. 2019ApJ...886..102S 2019ApJ...886..102S Cat. J/ApJ/886/102
Li et al. Paper II. 2020ApJ...903..119L 2020ApJ...903..119L
Tafoya et al. Paper III. 2021ApJ...913..131T 2021ApJ...913..131T
Morii et al. Paper IV. 2021ApJ...923..147M 2021ApJ...923..147M
Sakai et al. Paper V. 2022ApJ...925..144S 2022ApJ...925..144S
Sabatini et al. Paper VI. 2022ApJ...936...80S 2022ApJ...936...80S Cat. J/ApJ/936/80
Li et al. Paper VII. 2022ApJ...939..102L 2022ApJ...939..102L
Li et al. Paper VIII. 2023ApJ...949..109L 2023ApJ...949..109L Cat. J/ApJ/949/109
Morii et al. Paper IX. 2023ApJ...950..148M 2023ApJ...950..148M This catalog
Izumi at al. Paper X. 2024ApJ...963..163I 2024ApJ...963..163I
Morii et al. Paper XI. 2024ApJ...966..171M 2024ApJ...966..171M
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 04-Aug-2025