J/ApJS/280/33 The ALMA-QUARKS survey. III. Cores at 1.3mm (Yang+, 2025)
The ALMA-QUARKS survey.
III. Clump-to-core fragmentation and searches for high-mass starless cores.
Yang D., Liu H.-L., Liu T., Liu X., Xu F., Qin S.-L., Tej A., Garay G.,
Zhu L., Mai X., Jiao W., Zhang S., Dib S., Stutz A.M., Palau A.,
Sanhueza P., Zavagno A., Yang A.Y., Tang X., Tang M., Zhang Y., Garcia P.,
Zhang T., Saha A., Li S., Goldsmith P.F., Bronfman L., Lee C.W.,
Taniguchi K., Das S.R., Gorai P., Hoque A., Chen Li, Kou Z., Zhou J.,
Zhang Y., Toth L.V., Baug T., Shen X., Li C., Zou J., Das A., Nazeer H.,
Dewangan L.K., Hwang J., Chibueze J.O.
<Astrophys. J. Suppl. Ser., 280, 33 (2025)>
=2025ApJS..280...33Y 2025ApJS..280...33Y
ADC_Keywords: Interstellar medium; Molecular clouds; Star Forming Region;
Photometry, millimetric/submm
Keywords: Interstellar medium ; Dust continuum emission ;
Submillimeter astronomy ; Molecular clouds ; Star forming regions ;
Protoclusters ; Massive stars ; Protostars
Abstract:
The Querying Underlying mechanisms of massive star formation with
ALMA-Resolved gas Kinematics and Structures (QUARKS) survey observed
139 infrared-bright (IR-bright) massive protoclusters at 1.3mm
wavelength with the Atacama Large Millimeter/submillimeter Array
(ALMA). This study investigates clump-to-core fragmentation and
searches for candidate high-mass starless cores within IR-bright
clumps using combined ALMA 12m (C-2) and Atacama Compact Array 7m
data, providing ∼1" (∼0.02pc at 3.7kpc) resolution and ∼0.6mJy/beam
continuum sensitivity (∼0.3M☉ at 30K). We identified
1562 compact cores from 1.3 mm continuum emission using getsf.
Observed linear core separations (λobs) are significantly less
than the thermal Jeans length (λJ), with the
λobs/λJ ratios peaking at ∼0.2. This indicates that
thermal Jeans fragmentation has taken place within the IR-bright
protocluster clumps studied here. The observed low ratio of
λobs/λJ≪1 could be the result of evolving core
separation or hierarchical fragmentation. Based on associated
signatures of star formation (e.g., outflows and ionized gas), we
classified cores into three categories: 127 starless, 971 warm, and
464 evolved cores. Two starless cores have masses exceeding
16M☉, and represent high-mass candidates. The scarcity of such
candidates suggests that competitive accretion-type models could be
more applicable than turbulent core accretion-type models in high-mass
star formation within these IR-bright protocluster clumps.
Description:
The ALMA-Resolved gas Kinematics and Structures (QUARKS) survey
(PIs: Lei Zhu, Guido Garay, and Tie Liu; Project ID: 2021.1.00095.S;
Liu+ 2024, J/other/RAA/24.B5009) is a follow-up program to the ATOMS
survey in ALMA band 6 (∼1.3mm).
The QUARKS observations were optimized to cover the densest part of
139 IR-bright massive protocluster clumps. Two pointing observations
were allocated for each of them. Therefore, the QUARKS survey consists
of a total of 156 single pointings (e.g., fields).
In addition, for each field, the QUARKS observations were obtained
with three different ALMA configurations. That is, relatively low
(∼5"), moderate (∼1"), and high (∼0.3") angular resolution observations
were conducted by the ACA 7m array, ALMA 12m compact array C-2 (TM2)
and extended C-5 (TM1) configurations, respectively. ACA observations
were first completed in late 2022 May (Xu+ 2024RAA....24f5011X 2024RAA....24f5011X),
followed by TM2 and TM1 that proceeded until 2024 June.
See Section 2 for further explanations.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 112 1562 Core parameters measured by getsf
table4.dat 76 127 Derived parameters for candidate starless cores
table5.dat 107 1435 Derived parameters for candidate warm and evolved
cores
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See also:
J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)
J/A+AS/115/81 : A CS(2-1) survey of UC HII regions (Bronfman+, 1996)
J/A+A/426/97 : SIMBA survey. 1.2-mm/IRAS sources (Faundez+, 2004)
J/A+A/455/971 : Organic molecules in the Gal. center (Requena-Torres+, 2006)
J/A+A/487/993 : MAMBO Mapping of c2d Clouds and Cores (Kauffmann+, 2008)
J/A+A/530/A118 : G29.96-0.02 and G35.20-1.74 1mm and 3mm maps (Pillai+, 2011)
J/A+A/587/A47 : SMA 1.3mm image of OMC 1 North (Teixeira+, 2016)
J/ApJS/226/14 : MBPT calculations for Ne-like ions (Wang+, 2016)
J/A+A/619/A52 : Dense cores and YSOs in Lupus complex (Benedettini+, 2018)
J/A+A/619/A52 : Dense cores and YSOs in Lupus complex (Benedettini+, 2018)
J/ApJS/235/3 : Massive outflows assoc. with ATLASGAL clumps (Yang+, 2018)
J/ApJ/886/102 : 70um dark high-mass clumps with ALMA (Sanhueza+, 2019)
J/ApJS/248/24 : MUSTANG-2 Gal. Plane survey at 3mm (Ginsburg+, 2020)
J/MNRAS/496/2790 : ATOMS I Description & first look at G9.62+0.19 (Liu+, 2020)
J/ApJ/894/L14 : ALMA obs. of massive clouds in the CMZ (Lu+, 2020)
J/MNRAS/503/4601 : ALMA-IRDC from cloud to core scales (Barnes+, 2021)
J/MNRAS/505/2801 : ATOMS Paper III, massive star-forming regions (Liu+, 2021)
J/MNRAS/511/3618 : ATOMS ALMA 3 mm VII SiO clumps with ACA (Liu+, 2022)
J/A+A/664/A26 : W43-MM2&MM3 ministarburst ALMA data (Pouteau+, 2022)
J/A+A/657/A30 : W51 North ALMA 1.3 and 3mm images (Tang+, 2022)
J/MNRAS/510/3389 : High-mass star formation evol. trends (Urquhart+, 2022)
J/A+A/658/A160 : SEDIGISM survey, search for molecular outflows (Yang+, 2022)
J/MNRAS/510/4998 : ATOMS IV Gas clumps properties and SFRs (Zhang+, 2022)
J/MNRAS/526/2278 : TEMPO. Fragmentation and emission properties (Avison+, 2023)
J/ApJ/950/148 : ASHES. IX. Massive clumps with ALMA obs. (Morii+, 2023)
J/A+A/674/A75 : W43-MM1 and W43-MM2+MM3 ALMA datacubes (Nony+, 2023)
J/A+A/687/A217 : Massive protoclusters mapping (Dell'Ova+, 2024)
J/A+A/690/A33 : Core mass function in star formation (Louvet+, 2024)
J/AJ/167/228 : Physical properties of 221 clumps (Luo+, 2024)
J/ApJS/270/9 : ALMA obs. of massive & luminous clumps (Xu+, 2024)
J/A+A/696/A151 : ALMAGAL III. Compact source catalog (Coletta+, 2025)
J/A+A/697/A190 : ALMA-ATOMS survey. Weak hot core candidates (Li+, 2025)
J/A+A/696/A11 : ALMA-IMF XVII (Valeille-Manet+, 2025)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Source Source name (IHHMMm+DDMM_N, B1950)
15- 16 I2 --- Core [1/33] Core number in Source
18- 22 F5.2 kpc Dist [1.2/13] Distance to Source
24- 25 I2 h RAh [8/19] Hour of Right Ascension (ICRS)
27- 28 I2 min RAm Minute of Right Ascension (ICRS)
30- 34 F5.2 s RAs Second of Right Ascension (ICRS)
36 A1 --- DE- Sign of the Declination (ICRS)
37- 38 I2 deg DEd Degree of Declination (ICRS)
40- 41 I2 arcmin DEm Arcminute of Declination (ICRS)
43- 47 F5.2 arcsec DEs Arcsecond of Declination (ICRS)
49- 54 F6.4 arcsec AFWHM01 [0.74/3.9] Core semi-major axis from getsf
56- 61 F6.4 arcsec BFWHM01 [0.63/3.3] Core semi-minor axis from getsf
63- 71 F9.5 deg theta01 Core position angle from getsf
73- 80 F8.2 mJy Flux [0.5/11139] Integrated 1.3mm flux density
82- 86 F5.2 mJy e_Flux [0.05/55.4] Uncertainty in Flux
88- 94 F7.2 mJy/beam PkFlux [0.15/1188] Peak 1.3mm flux density per beam
96- 100 F5.2 mJy/beam e_PkFlux [0.03/25] Uncertainty in PeakFlux
102- 105 I4 --- Sig [5/3580] Detection significance from
monochromatic single scales
107- 112 I6 --- Good [1/704300] Monochromatic goodness combining
significance and signal-to-noise ratio
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Source Source name (IHHMMm+DDMM_N, B1950)
15- 16 I2 --- Core [2/20] Core number in Source
18- 19 I2 h RAh [8/19] Hour of Right Ascension (ICRS)
21- 22 I2 min RAm Minute of Right Ascension (ICRS)
24- 28 F5.2 s RAs Second of Right Ascension (ICRS)
30 A1 --- DE- Sign of the Declination (ICRS)
31- 32 I2 deg DEd Degree of Declination (ICRS)
34- 35 I2 arcmin DEm Arcminute of Declination (ICRS)
37- 41 F5.2 arcsec DEs Arcsecond of Declination (ICRS)
43- 47 I5 AU Rad [535/10540] Radius
49 I1 --- Nl [1/6] Number of molecular lines detected
for each core
51- 52 I2 K Temp [19/45] Dust temperature of parent clump
54- 58 F5.2 Msun Mass-up [0.16/21] Upper bound on core mass (1)
60- 64 F5.2 Msun Mass-lo [0.1/13.1] Lower bound on core mass (1)
66- 70 F5.1 10+6cm-3 nH2-20k [0.1/148] Molecular hydrogen number
density, for 20K temperature
72- 74 F3.1 g.cm-2 Sigma20K [0.1/8.7] Surface density, for 20K
temperature
76 A1 --- Flag [*] * = Candidate high-mass starless core
--------------------------------------------------------------------------------
Note (1): The upper and lower masses were calculated corresponding to
the assumed 20K typical for candidate starless cores in the IR-bright
environment and the average temperature of the parental clump,
respectively. Note that since there are 2 cores (i.e., in I13295-6152
clumps) whose parental clump has an average temperature slightly lower
than 20K, the upper and lower mass estimates were switched manually.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Source Source name (IHHMMm+DDMM_N, B1950)
15- 16 I2 --- Core [1/33] Core number in Source
18- 19 I2 h RAh [8/19] Hour of Right Ascension (ICRS)
21- 22 I2 min RAm Minute of Right Ascension (ICRS)
24- 28 F5.2 s RAs Second of Right Ascension (ICRS)
30 A1 --- DE- Sign of the Declination (ICRS)
31- 32 I2 deg DEd Degree of Declination (ICRS)
34- 35 I2 arcmin DEm Arcminute of Declination (ICRS)
37- 41 F5.2 arcsec DEs Arcsecond of Declination (ICRS)
43- 47 I5 AU Rad [266/15496] Radius
49- 51 I3 --- Nl [2/291] Number of molecular lines detected
for each core
53- 57 F5.1 K Temp [30/100] Dust temperature (1)
59- 65 F7.2 Msun Mass [0.01/2654] Core mass
67- 73 F7.2 Msun e_Mass [0/1098] Uncertainty in Mass
75- 82 F8.2 10+5cm-3 Density [0.3/13335] Molecular hydrogen number
density
84- 89 F6.1 10+5cm-3 e_Density [0.2/5553] Uncertainty in Density
91- 96 F6.2 g.cm-2 Sigma [0.05/196] Surface density
98- 101 F4.1 g.cm-2 e_Sigma [0/81] Uncertainty in Sigma
103- 107 A5 --- Evol Evolutionary stage of each core (2)
--------------------------------------------------------------------------------
Note (1): The dust temperature for the warm and evolved core
candidates was assumed to be 30K and 100K, respectively
Note (2): The evolutionary stage of each core are as follows:
WC = warm core candidate (971 occurrences)
HMC = hot molecular core candidate (314 occurrences)
Hii-h = UCHii core with a high line richness (Nl≥15; 63 occurrences)
Hii-l = UCHii core with a low line richness (6<Nl<15; 87 occurrences)
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History:
From electronic version of the journal
License: CC-BY-4.0
References:
Liu et al. Paper I. 2024RAA....24b5009L 2024RAA....24b5009L Cat. J/other/RAA/24.B5009
Xu et al. Paper II. 2024RAA....24f5011X 2024RAA....24f5011X
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 04-Jun-2026