J/ApJ/949/109 ASHES. VIII. Dynamics of embedded dense cores (Li+, 2023)
The ALMA Survey of 70um dark High-mass clumps in Early Stages (ASHES).
VIII. Dynamics of embedded dense cores.
Li S., Sanhueza P., Zhang Q., Guido G., Sabatini G., Morii K., Lu X.,
Tafoya D., Nakamura F., Izumi N., Tatematsu K., Li F.
<Astrophys. J., 949, 109 (2023)>
=2023ApJ...949..109L 2023ApJ...949..109L
ADC_Keywords: Molecular clouds; Velocity dispersion; Star Forming Region;
Interstellar medium; Millimetric/submm sources
Keywords: Infrared dark clouds ; Star forming regions ; Star formation ;
Massive stars ; Protostars ; Interstellar line emission ;
Interstellar medium ; Protoclusters
Abstract:
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.
Description:
In this paper, we present sensitive, high-angular resolution
(∼0.023pc) and high-sensitivity observations of the gas and dust
emission within twelve 70um dark infrared dark clouds (IRDCs) from the
Atacama Large Millimeter/submillimeter Array (ALMA) Survey of 70um
dark High-mass clumps in Early Stages (ASHES;
Sanhueza+ 2019, J/ApJ/886/102).
The observations were carried out with the Atacama Large
Millimeter/submillimeter Array (ALMA), located in the Llano de
Chajnantor, Chile, during the ALMA cycles (3) and (4) (project ID:
2015.1.01539.S, PI: Sanhueza). These observations covered both the
continuum and molecular line emission toward 12 massive 70um dark
high-mass clumps located in the Galactic plane.
The angular resolution of the images is ∼1.2", corresponding to 4800au
(or 0.023pc) at the averaged source distance of 4kpc.
See Section 2.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 68 12 Summary of IRDC clump properties
table2.dat 66 294 *Summary of dense cores properties
table3.dat 114 294 *Summary of N2D+ and DCO+ lines properties
--------------------------------------------------------------------------------
Note on table2.dat and table3.dat:
Summary statistics (Table 2):
------------------------------------------------------------------------
Mgas Rcore NH2pk Sigma TNH3 SigTot Mvir aVir aG aK
------------------------------------------------------------------------
Minimum 0.05 0.004 0.06 0.06 6.5 0.21 0.22 0.15 0.75 2.36
Maximum 31.66 0.047 4.95 3.39 22.8 0.79 8.60 9.37 45.74 82.94
Mean 1.79 0.014 0.57 0.51 14.3 0.38 1.89 1.45 6.86 13.12
Median 0.77 0.013 0.36 0.34 14.4 0.35 1.25 0.90 4.66 9.45
------------------------------------------------------------------------
Summary statistics (Table 3):
------------------------------------------------------------------------
Ta-N2D+ sig-N2D+ sign-N2D+ M-N2D+ Ta-DCO+ sig-DCO+ sign-DCO+ M-DCO+
------------------------------------------------------------------------
Min 0.11 0.10 0.03 0.16 0.11 0.10 0.03 0.13
Max 1.74 0.77 0.77 4.59 1.83 0.53 0.52 2.54
Mean 0.38 0.32 0.30 1.43 0.45 0.23 0.21 0.95
Med 0.33 0.30 0.29 1.34 0.41 0.22 0.20 0.91
------------------------------------------------------------------------
--------------------------------------------------------------------------------
See also:
J/ApJ/566/945 : Massive star forming regions at 1.2mm (Beuther+, 2002)
J/ApJ/646/1009 : Structures of dust in Perseus molecular cloud (Kirk+, 2006)
J/ApJ/653/1325 : Galactic distribution of infrared dark clouds (Simon+, 2006)
J/ApJ/684/1240 : Prestellar cores in Perseus, Serpens & Oph (Enoch+, 2008)
J/A+A/487/993 : MAMBO Mapping of c2d Clouds and Cores (Kauffmann+, 2008)
J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)
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/549/A45 : ATLASGAL Compact Source Catalog: 330<l<21 (Contreras+, 2013)
J/ApJ/790/84 : Ammonia in high-mass star formation regions (Lu+, 2014)
J/ApJ/815/130 : High-mass molecular clumps from MALT90 (Guzman+, 2015)
J/MNRAS/456/2041 : Fragmentation in filamentary MoCs (Contreras+ 2016)
J/other/PASA/33.30 : MALT90 Catalogue (Rathborne+, 2016)
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/MNRAS/477/2220 : Larson relations in massive clumps (Traficante+, 2018)
J/MNRAS/483/3146 : Young stellar objects NH3 mapping (Billington+, 2019)
J/ApJ/886/102 : ALMA obs. of 70um dark clumps (ASHES) (Sanhueza+, 2019)
J/MNRAS/496/2790 : ATOMS I. A first look at G9.62+0.19 (Liu+, 2020)
J/MNRAS/503/4601 : ALMA-IRDC from cloud to core scales (Barnes+, 2021)
J/ApJ/912/156 : Core kinematics in the Dragon IRDC from ALMA (Kong+, 2021)
J/ApJ/936/80 : ASHES. VI. Core-Scale CO Depletion (Sabatini+, 2022)
J/ApJS/264/35 : C18O dense cores in Orion A MoC (Takemura+, 2023)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- AGAL Clump name (GLLL.lll+BB.bbb)
17- 23 A7 --- SName Short clump name used in this article (GLLL.ll)
25- 27 F3.1 kpc Dist [2.9/5.4] Distance
29- 31 F3.1 10+3Msun Mgas [0.6/5.2] Clump gas mass
33- 35 F3.1 10+3Msun e_Mgas [0.1/1.1] Uncertainty in Mgas
37- 39 F3.1 10+3Msun Mvir [0.1/4.4] Virial mass
41- 43 F3.1 10+3Msun e_Mvir [0.1/1] Uncertainty in Mvir
45- 47 F3.1 --- aVir [0.2/5.7] Virial parameter, α
49- 51 F3.1 --- e_aVir [0.1/1.7] Uncertainty in aVir
53- 58 F6.2 km/s vLSR [-87.9/80] Source velocity
60- 63 F4.2 km/s sigma [0.56/3.1] Velocity dispersion (1)
65- 68 F4.2 km/s e_sigma [0.05/0.2] Uncertainty in sigma
--------------------------------------------------------------------------------
Note (1): N2H+ J=1-0 emission was used to derive the velocity
dispersion for the clumps, except for G028.273-00.167,
G337.541-00.082, and G340.222-00.167. The former clump was
obtained using NH2D JKa,Kc=11,1->10,1 emission and the latter
two clumps were derived from HNC J=1-0 emission.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- SName Short name of the parental IRDC as given
in Table 1 (G1)
9- 10 I2 --- Core [1/39] Core number in Clump
12- 16 F5.2 Msun Mgas [0.05/31.7] Core gas mass
18- 22 F5.3 pc Rcore [0.004/0.05] Core radius, parsec
24- 27 F4.2 10+23cm-2 NH2pk [0.06/4.95] Peak H2 density
29- 32 F4.2 g/cm2 Sigma [0.06/3.4] Core-averaged surface density
34- 37 F4.1 K TNH3 [6.5/22.8] Gas temperature derived from
NH3
39- 42 F4.2 km/s sigTot [0.2/0.8]? Total velocity dispersion,
from N2D+ or DCO+
44- 47 F4.2 Msun Mvir [0.2/8.61]? Core virial mass
49- 52 F4.2 --- aVir [0.15/9.4]? Virial parameter
54- 58 F5.2 pc/Myr2 aG [0.7/45.8] Gravitational acceleration
parameter
60- 64 F5.2 pc/Myr2 aK [2.36/83]? Kinetic acceleration parameter
66 I1 --- SF [0/3]? Star formation category (1)
--------------------------------------------------------------------------------
Note (1): Star formation category; code as follows:
0 = no star formation signature (prestellar core candidate);
1 = the "outflow core"
2 = "warm core"
3 = "warm & outflow core"
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- SName Short name of the parental IRDC as
in Table 1 (G1)
9- 10 I2 --- Core [1/39] Core number in Clump
12- 15 F4.2 K Ta-N2D+ [0.1/1.8]? Antenna temperature, N2D+
17- 20 F4.2 K e_Ta-N2D+ [0.02/0.2]? Uncertainty in Ta-N2D+
22- 27 F6.2 km/s vLSR-N2D+ [-88.4/81]? Core central velocity
29- 32 F4.2 km/s e_vLSR-N2D+ [0.01/0.2]? Uncertainty in vLSR-N2D+
34- 37 F4.2 km/s sig-N2D+ [0.1/0.8]? Observed velocity dispersion, N2D+
39- 42 F4.2 km/s e_sig-N2D+ [0.01/0.2]? Uncertainty in sigma-N2D+
44- 47 F4.2 km/s sign-N2D+ [0.03/0.8]? Non-thermal linewidth, N2D+
49- 52 F4.2 km/s e_sign-N2D+ [0.01/0.2]? Uncertainty in sigma-nth-N2D+
54- 57 F4.2 --- M-N2D+ [0.16/4.6]? Mach number, N2D+
59- 62 F4.2 --- e_M-N2D+ [0.06/0.71]? Uncertainty in M-N2D+
64- 67 F4.2 K Ta-DCO+ [0.1/1.83]? Antenna temperature, DCO+
69- 72 F4.2 K e_Ta-DCO+ [0.01/0.2]? Uncertainty in Ta-DCO+
74- 79 F6.2 km/s vLSR-DCO+ [-88.2/80]? Core central velocity
81- 84 F4.2 km/s e_vLSR-DCO+ [0.02/0.2]? Uncertainty in vLSR-DCO+
86- 89 F4.2 km/s sig-DCO+ [0.1/0.6]? Observed velocity dispersion, DCO+
91- 94 F4.2 km/s e_sig-DCO+ [0.03/0.4]? Uncertainty in sigma-DCO+
96- 99 F4.2 km/s sign-DCO+ [0.03/0.6]? Non-thermal linewidth, DCO+
101- 104 F4.2 km/s e_sign-DCO+ [0.03/0.4]? Uncertainty in sigma-nth-DCO+
106- 109 F4.2 --- M-DCO+ [0.13/2.6]? Mach number, DCO+
111- 114 F4.2 --- e_M-DCO+ [0.13/1.9]? Uncertainty in M-DCO+
--------------------------------------------------------------------------------
Global notes:
Note (G1): In tables 2 and 3, clump name "G340.24" was a misprint for "G340.23";
corrected at CDS.
Acknowledgements:
Shanghuo Li [shli at nju.edu.cn]
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 This catalog
Morii et al. Paper IX. 2023ApJ...950..148M 2023ApJ...950..148M Cat. J/ApJ/950/148
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] 16-Jul-2025