J/AJ/167/228 Physical properties of 221 clumps (Luo+, 2024)
Implication of the Velocity Dispersion Scalings on High-mass Star Formation in
Molecular Clouds.
Luo A.-X., Liu H.-L., Qin S.-L., Yang D.-T., Pan S.
<Astron. J., 167, 228 (2024)>
=2024AJ....167..228L 2024AJ....167..228L
ADC_Keywords: YSOs; Star Forming Region; Interstellar medium
Keywords: Star formation ; Interstellar dynamics ; Interstellar medium
Abstract:
This paper is aimed at exploring the implications of
velocity-dispersion scalings on high-mass star formation in molecular
clouds, including the scalings of Larson's linewidth-size (σ-R)
and ratio-mass surface density (L-Σ; here L=σ/R0.5). We
have systematically analyzed the σ parameter of well-selected
221 massive clumps, complemented with published samples of other
hierarchical density structures of molecular clouds over spatial
scales of 0.01-10pc. Those massive clumps are classified into four
phases: quiescent, protostellar, HII region, and PDR clumps in an
evolutionary sequence. The velocity dispersion of clumps increases
overall with the evolutionary sequence, reflecting enhanced stellar
feedback in more evolved phases. The relations of σ-R and
L-Σ are weak with the clump sample alone, but become evident
when combined with others spanning a much wider spatial scales. For
σ-R, its tight relation indicates a kinematic connection between
hierarchical density structures, supporting theoretical models of
multiscale high-mass star formation. From the L-Σ relation,
cloud structures can be found to transition from overvirial state
(αvir>2) to subvirial state (αvir<2) as they become
smaller and denser, indicating a possible shift in the governing force
from turbulence to gravity. This implies that the multiscale physical
process of high-mass star formation hinges on the self-gravity of
subvirial molecular clouds. However, the influence of turbulence may
not be dismissed until large-scale clouds attain a subvirial state.
This is pending confirmation from future multiscale kinematic
observations of molecular clouds with uniform observing settings.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 111 221 Physical properties of clumps
--------------------------------------------------------------------------------
See also:
J/A+A/481/345 : SED evolution in massive young stellar obj (Molinari+, 2008)
J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)
J/ApJ/723/492 : Physical property GRS molecular clouds (Roman-Duval+, 2010)
J/MNRAS/443/1555 : ATLASGAL massive star forming clumps (Urquhart+, 2014)
J/ApJ/815/130 : High-mass molecular clumps from MALT90 (Guzman+, 2015)
J/A+A/575/A79 : SPIRE 250um maps of 4 molecular clouds (Schneider+, 2015)
J/other/PASA/33.30 : MALT90 Catalogue (Rathborne+, 2016)
J/MNRAS/477/2220 : Larson relations in massive clumps (Traficante+, 2018)
J/MNRAS/473/1059 : Complete sample Galactic clump properties (Urquhart+, 2018)
J/MNRAS/510/3389 : High-mass * formation evolutionary trends (Urquhart+, 2022)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID [1/221] Clump sequential identifier
5- 22 A18 --- Sname Clump name, AGALDDD.ddd-DD.ddd
24- 30 F7.3 deg GLON [10.168/348.759] Galactic longitude
32- 37 F6.3 deg GLAT [-1.042/1.176] Galactic latitude
39- 42 F4.2 pc Rad [0.15/4.08] Clump radius (1)
44- 47 F4.2 pc e_Rad [0.03/0.82] Uncertainty in Radius (1)
49- 52 F4.2 g.cm-2 Sigma [0.04/0.42] average mass surface density (1)
54- 57 F4.2 g.cm-2 e_Sigma [0.0/0.05] Uncertainty in Sigma (1)
59- 63 I5 Msun Mass [27/64979] Clump mass
65- 69 I5 Msun e_Mass [10/19490] Uncertainty in Mass
71- 77 I7 Lsun Lum [5/1040858]? Clump luminosity (2)
79- 82 F4.2 km.s-1 dVel [0.23/3.2] Clump velocity dispersion at CO
84- 87 F4.2 km.s-1 e_dVel [0.02/0.21] Uncertainty in dV
89- 93 F5.2 --- alpha [0.11/11.65] Virial parameter
95- 98 F4.2 --- e_alpha [0.04/4.43] Uncertainty in alpha
100-111 A12 --- Phase Evolutionary phase
--------------------------------------------------------------------------------
Note (1): The clump radius and average mass surface density are
retrieved from Guzman+, 2015, J/ApJ/815/130.
Note (2): The clump luminosity is obtained from Contreras+,
2017MNRAS.466..340C 2017MNRAS.466..340C and Urquhart+, 2022, J/MNRAS/510/3389. Blank
(null) values for the luminosity correspond to cases where the
luminosity data for these clumps was not collected.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 13-Jun-2024