J/A+A/637/A40 HMSCs classification and physical parameters (Zhang+, 2020)
HII regions and high-mass starless clump candidates. I: Catalogs and properties.
Zhang S., Zavagno A., Yuan J., Liu H., Figueira M., Russeil D.,
Schuller F., Marsh K.A., Wu Y.
<Astron. Astrophys. 637, A40 (2020)>
=2020A&A...637A..40Z 2020A&A...637A..40Z (SIMBAD/NED BibCode)
ADC_Keywords: H II regions ; Millimetric/submm sources ; Associations, stellar ;
Interstellar medium
Keywords: stars: formation - H II regions - submillimeter: ISM
Abstract:
The role of ionization feedback on high-mass (>8M☉) star
formation is still highly debated. Questions remain concerning the
presence of nearby HII regions changes the properties of early
high-mass star formation and whether H ii regions promote or inhibit
the formation of high-mass stars.
To characterize the role of HII regions on the formation of high-mass
stars, we study the properties of a sample of candidates high-mass
starless clumps (HMSCs), of which about 90% have masses larger than
100 Msun. These high-mass objects probably represent the earliest
stages of high-mass star formation; we search if (and how) their
properties are modified by the presence of an HII region.
We took advantage of the recently published catalog of HMSC
candidates. By cross matching the HMSCs and HII regions, we classified
HMSCs into three categories: 1) The HMSCs associated with HII regions
both in the position in the projected plane of the sky and in
velocity; 2) HMSCs associated in the plane of the sky, but not in
velocity; and 3) HMSCs far away from any HII regions in the projected
sky plane. We carried out comparisons between associated and
non-associated HMSCs based on statistical analyses of multiwavelength
data from infrared to radio.
We show that there are systematic differences of the properties of
HMSCs in different environments. Statistical analyses suggest that
HMSCs associated with HII regions are warmer, more luminous, more
centrally-peaked and turbulent. We also clearly show, for the first
time, that the ratio of bolometric luminosity to envelope mass of
HMSCs (L/M) could not be a reliable evolutionary probe for early
massive star formation due to the external heating effects of the HII
regions.
We show HMSCs associated with HII regions present statistically
significant differences from HMSCs far away from HII regions,
especially for dust temperature and L/M. More centrally peaked and
turbulent properties of HMSCs associated with HII regions may promote
the formation of high-mass stars by limiting fragmentation.
High-resolution interferometric surveys toward HMSCs are crucial to
reveal how HII regions impact the star formation process inside HMSCs.
Description:
This table (Table 4 in the paper) consists of the basic properties of
high-mass starless clump candidates that are updated by this work.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 157 463 Basic properties of high-mass starless
clump candidates
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See also:
J/ApJS/231/11 : ATLASGAL high-mass starless clump candidates (Yuan+, 2017)
J/MNRAS/473/1059 : Complete sample of Galactic clump properties
(Urquhart+, 2018)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Name Name of sources, GLLL.llll+B.bbb
18- 21 F4.1 K Tdust Dust temperature (1)
23- 30 E8.3 cm-3 nH2 Molecular hydrogen number density
32- 39 E8.3 cm-3 e_nH2 Error of molecular hydrogen number density
41- 48 E8.3 cm-2 NH2 Molecular hydrogen column density
50- 57 E8.3 cm-2 e_NH2 Error of molecular hydrogen column
density (2)
59- 66 E8.3 Msun Mclump Mass of clump
68- 75 E8.3 Msun e_Mclump Error of clump mass
77- 84 E8.3 Lsun Lclump Luminosity of clump
86- 93 E8.3 Lsun e_Lclump Error of clump luminosity
95-100 F6.3 Lsun/Msun L/M Ratio of luminosity to mass
102-107 F6.3 Lsun/Msun e_L/M Error of the ratio of luminosity to mass
109-113 F5.3 pc rpc Size of clump
115-118 F4.2 -- Ecc Eccentricity of the clump
120-126 F7.2 km/s Vlsr Velocity of the clump
128-132 F5.2 km/s e_Vlsr ? Error of the clump velocity
134-138 F5.2 kpc Dist Distance of clump (3)
140-144 F5.2 kpc e_Dist Error of the distance
146-152 A7 --- KDA The ways used to solve the Kinematic
Distance Ambiguities (4)
154-155 A2 --- SimpleAss The classification results that describes
the association relation between HII
regions and high-mass starless clump
candidates (5)
157 A1 --- Shape More detailed description for the
morphology of environment of clump (6)
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Note (1): The typical error of dust temperature estimated by Yuan et al.
(2017ApJS..231...11Y 2017ApJS..231...11Y, Cat. J/ApJS/231/11)
Note (2): The typical error of column density is estimated about 15% from
Yuan et al. (2017ApJS..231...11Y 2017ApJS..231...11Y, Cat. J/ApJS/231/11)
Note (3): The distance error is taken from the results of distance calculator
and its typical value is less than 1kpc.
The distance errors are propagated to the calculation of other physical
parameters. See details in the accompanying paper.
Note (4): We solve the KDA with several ways, as follows:
IR DARK = IR extinction
HISA = HI self-absorption
Z H = The scale height in the Galactic plane
TANGENT = The tangent line of sight
LITERAT = The literature in Urquhart et al.
(2018MNRAS.473.1059U 2018MNRAS.473.1059U, Cat. J/MNRAS/473/1059)
See Appendix A in the associated paper for more information.
Note (5): The association relationship between HII regions and high-mass
starless clumps, see the detailed in the Section 4 in the associated paper.
Associations as follows:
AS = HMSC is in 2Reff of the HII region and its vlsr difference with the
HII region is ≤7km/s
PA = HMSCs is in 2Reff of the HII region but we do not know vlsr of the HII
region or the vlsr difference is >7km/s
NA = the separation between the HMSC and the HII region is> 2Reff
Note (6): The detailed explanation about the morphology is in Appendix B
Morphology as follows:
C = clumpy
F = filament
I = isolated
S = sculptured or shell
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Acknowledgements:
Siju Zhang, sijuzhangastro(at)gmail.com
(End) Siju Zhang [LAM, France], Patricia Vannier [CDS] 26-Mar-2020