J/MNRAS/505/2801 ATOMS Paper III, massive star-forming regions (Liu+, 2021)
ATOMS ALMA three-millimeter observations of massive star-forming regions
III. Catalogues of candidate hot molecular cores and hyper/ultra compact
H II regions.
Liu H.-L., Liu T., Evans II N.J., Wang K., Garay G., Qin S.-L., Li S.,
Stutz A., Goldsmith P.F., Liu S.-Y., Tej A., Zhang Q., Juvela M., Li D.,
Wang J.-Z., BronfmaN L., Ren Z., Wu Y.-F., Kim K.-T., Lee C.W.,
Tatematsu K., Cunningham M.R., Liu X.-C., Wu J.-W., Hirota T., Lee J.-E.,
Li P.-S., Kang S.-J., Mardones D., Ristorcelli I., Zhang Y., Luo Q.-Y.,
Toth L.V., Yi H.-W., Yun H.-S., Peng Y.-P., Li J., Zhu F.-Y., Shen Z.-Q.,
Baug T., Dewangan L.K., Chakali E., Liu R., Xu F.-W., Wang Y., Zhang C.,
Li J., Zhang C., Zhou J., Tang M., Xue Q., Issac N., Soam A.,
Alvarez-Gutierrez R.H.
<Mon. Not. R. Astron. Soc., 505, 2801-2818 (2021)>
=2021MNRAS.505.2801L 2021MNRAS.505.2801L (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Star Forming Region ; H II regions ;
Radio continuum ; Radio lines ; Photometry, millimetric/submm ;
Spectra, millimetric/submm
Keywords: stars: formation - stars: kinematics and dynamics - ISM: clouds -
H II regions
Abstract:
We have identified 453 compact dense cores in 3 mm continuum emission
maps in the ALMA Three-millimetre Observations of Massive Star-forming
regions survey, and compiled three catalogues of high-mass
star-forming cores. One catalogue, referred to as hyper/ultra compact
(H/UC)-H II catalogue, includes 91 cores that enshroud H/UC H II
regions as characterized by associated compact H40α emission. A
second catalogue, referred to as pure s-cHMC, includes 31 candidate
hot molecular cores (HMCs) showing rich spectra (N ≥ 20 lines) of
complex organic molecules (COMs) and not associated with H/UC-H ii
regions. The third catalogue, referred to as pure w-cHMC, includes 51
candidate HMCs with relatively low levels of COM richness and not
associated with H/UC-H II regions. These three catalogues of dense
cores provide an important foundation for future studies of the early
stages of high-mass star formation across the Milky Way. We also find
that nearly half of H/UC-H II cores are candidate HMCs. From the
number counts of COM-containing and H/UC-H II cores, we suggest that
the duration of high-mass protostellar cores showing chemically rich
features is at least comparable to the lifetime of H/UC-H II regions.
For cores in the H/UC-H II catalogue, the width of the H40α line
increases as the core size decreases, suggesting that the non-thermal
dynamical and/or pressure line-broadening mechanisms dominate on the
smaller scales of the H/UC-H II cores.
Description:
With the ATOMS survey data (same as see Paper I 2020MNRAS.496.2790L 2020MNRAS.496.2790L,
Cat. J/MNRAS/496/2790 and Paper II 2020MNRAS.496.2821L 2020MNRAS.496.2821L, Cat.
J/MNRAS/496/2821) , in this paper we aim to establish catalogues of a
large sample of both candidate HMCs and H/UC-H II regions as a
crucial foundation for future studies for the early stages of
high-mass star formation. The ATOMS survey targeted a large sample of
146 IRAS clumps (Bronfman, Nyman & May 1996A&AS..115...81B 1996A&AS..115...81B, Cat.
J/A+AS/115/81; Liu et al. 2016ApJ...829...59L 2016ApJ...829...59L ).
(please see section 2 alma observations for mere details).
The ACA and 12 m array data were calibrated and imaged separately
with the casa software package version 5.6 (McMullin et al. 2007 ASP
Conf. Ser. Vol. 376, Astronomical Data Analysis Software and Systems
XVI. Astron. Soc. Pac, San Francisco, p. 127). More details on the
data reduction can be found in Paper I (Liu T.et al.
2020MNRAS.496.2790L 2020MNRAS.496.2790L, Cat. J/MNRAS/496/2790) and Paper II (Liu T. et
al. 2020MNRAS.496.2821L 2020MNRAS.496.2821L, Cat. J/MNRAS/496/2821). To extract compact
cores (observational and physical properties) from the 3 mm
continuum maps, we make use of both the Dendrogram algorithm and
casaimfit function. As a result, we finally obtained 453 cores from
the 146 ATOMS target clumps.
Hereafter, we search for candidate HMCs and H/UC-HII cores. The
advantage of the ATOMS survey strategy is that the two wide SPWs 7 and
8 cover many transitions of the COMs (i.e. HMC tracers) and the
H40α transition (the ionized gas tracer).
If the H40α emission appears compact and is spatially associated
with the compact continuum core, the core will be classified as an
H/UC-HII core. Following this rule, we finally obtain 91 H/UC-HII
cores. Their parameters determined are given in table1.dat.
To quantitatively describe the chemical richness of a core, we use the
number of lines (Nline). These spectral windows cover tens of
transitions from COMs (e.g. CH3OCHO, CH3CHO, CH3OH, C2H5CN)
that are usually detectable in an HMC, and only two or three transitions
of non-HMC-tracer molecules (i.e. CS (2-1), SO (3-2) or H2CO.
Counting the emission lines is therefore useful in a search for the
COM-containing cores.
Following the above criteria, 138 COM-containing cores were selected.
However we only exhibit COM-containing cores without H/UC-H II
spectral signatures. Thus, the table2.dat refers to 31 pure strong
cores with Nline ≥ 20 while the table3.dat represents 51 pure weak
cores with 5 ≤ Nline ≤ 20.
Finally, the remaining 280 cores lack observationally quantifiable
metrics for association into any of the three categories above. Hence,
we refer to these as 'unknown cores' as their properties are shown in
the table4.dat (see section 3.3 for more details).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 162 91 Parameters of 91 H/UC-HII cores from the
ATOMS survey's clumps
table2.dat 131 31 Parameters of the COM-containing
but not H/UC-HII associated cores
with Nline ≥ 20 (or pure s-cHMC)
table3.dat 129 51 Parameters of the COM-containing
but not H/UC-HII associated cores with
5 ≤ Nline ≤ 20 (or pure w-cHMC)
table4.dat 135 280 Parameters of the 'unknown' cores
(i.e. no signature of H/UC-H II nor cHMC)
--------------------------------------------------------------------------------
See also:
J/MNRAS/496/2790 : ATOMS I Description and a first look at G9.62+0.19
(Liu+, 2020)
J/MNRAS/496/2821 : ATOMS II Compact objects in ACA observations (Liu+, 2020)
J/A+AS/115/81 : A CS(2-1) survey of UC HII regions (Bronfman+, 1996)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Clump Name Clump
13- 29 A17 --- Core Galactic Name core
31 A1 --- n_Core Note on Core name (1)
33- 36 F4.1 kpc D Distance
38- 40 F3.1 kpc E_D Upper uncertainty of D (E_D)
42- 44 F3.1 kpc e_D Lower uncertainty of D (e_D)
46- 49 F4.1 arcsec MajAxis Full-Width at Half-Maximum (FWHM)
major axis (FWHMmaj) (2)
51- 54 F4.1 arcsec MinAxis Full-Width at Half-Maximum (FWHM)
minor axis (FWHMmin) (2)
56- 60 F5.1 deg PA Position Angle (PA)
62- 65 F4.1 arcsec MajAxisdec Deconvolved Full-Width at Half-Maximum
(FWHMdec) major axis (FWHMdecmaj) (2)
67- 70 F4.1 arcsec MinAxisdec Deconvolved Full-Width at Half-Maximum
(FWHMdec) minor axis (FWHMdecmin) (2)
72- 77 F6.1 mJy F3mm The core-integrated 3 mm flux (Fint3mm)
79- 83 F5.1 mJy e_F3mm Mean error on F3mm (Fint3mm_error) (3)
85- 90 F6.1 mJy/beam Fp3mm The core-peak flux (Fp3mm)
92- 95 F4.1 mJy/beam e_Fp3mm Mean error on (Fp3mm_error) (3)
97-100 F4.1 10-2pc Rcore The radii of the cores (Rcore) (4)
102-104 F3.1 10-2pc E_Rcore Upper uncertainty of Rcore (E_Rcore)
(5)
106-108 F3.1 10-2pc e_Rcore Lower uncertainty of Rcore (e_Rcore)
(5)
110-115 F6.1 mJy/beam FH40a The measured line peak intensity of
the H40alpha line (FpH40alpha) (6)
117-120 F4.1 mJy/beam e_FH40a Mean error on FH40a (FH40a_error) (3)
122-127 F6.1 km/s VH40a The velocity centroid of the H40aplha
line (VlsrH40alpha) (6)
129-131 F3.1 km/s e_VH40a Mean error on VH40alpha
(VH40alpha_error)
133-136 F4.1 km/s DVH40a FWHM line width of the H40alpha line
(DeltaVlsrH40alpha) (6)
138-140 F3.1 km/s e_DVH40a Mean error on FWHMH40a
(DeltaVlsrH40alpha_error)
142-145 F4.1 arcsec MajAxisdecH40a Deconvolved FWHM (FWHMdec) major axis
of the H40aplha line
(FWHMdecH40alphamaj) (2)
147-149 F3.1 arcsec MinAxisdecH40a Deconvolved FWHM (FWHMdec) minor axis
of the H40aplha line
(FWHMdecH40alphamin) (2)
151-154 F4.1 10-2pc RcoreH40a The radii of the cores measured with
the H40aplha line (RH40alphacore) (4)
156-158 F3.1 10-2pc E_RcoreH40a Upper uncertainty of RcoreH40a
(E_Ralphacore) (5)
160-162 F3.1 10-2pc e_RcoreH40a Lower uncertainty of RcoreH40a
(e_Ralphacore) (5)
-------------------------------------------------------------------------------
Note (1): The * symbol after the core name indicates that this core is
associated with a COM-containing core or COM-containing cores.
Note (2): FWHM is the measured core size, while FWHMdec is the corresponding
deconvolved size.
Note (3): The erros on the fluxes come from the 2D Gaussian fitting in the
core extraction.
Note (4): Rcore follows the form of Reff/3600 * pi/180 * D, where Reff is the
effective radius equal to sqrt(FWHMdec)/2, and D is the distance
of the core. Calculated assuming the same distance as that of their
natal clumps (Liu et al. 2020MNRAS.496.2790L 2020MNRAS.496.2790L, Cat. J/MNRAS/496/2790).
Note (5): The errors on Rcore and RH40α core mainly result from
the distance uncertainties.
Note (6): Obtained by fitting a single-Gaussian component to the beam-averaged
spectrum of H40α.
-------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Clump Name Clump
13- 29 A17 --- Core Galactic Name core
31- 34 F4.1 kpc D Distance
36- 38 F3.1 kpc E_D Upper uncertainty of D (E_D)
40- 42 F3.1 kpc e_D Lower uncertainty of D (e_D)
44- 46 F3.1 arcsec MajAxis Full-Width at Half-Maximum (FWHM) major
axis (FWHMmaj) (G1)
48- 50 F3.1 arcsec MinAxis Full-Width at Half-Maximum (FWHM) minor
axis (FWHMmin) (G1)
52- 56 F5.1 deg PA Position Angle (PA)
58- 60 F3.1 arcsec MajAxisdec Deconvolved Full-Width at Half-Maximum
(FWHMdec) major axis (FWHMdecmaj) (G1)
62- 64 F3.1 arcsec MinAxisdec Deconvolved Full-Width at Half-Maximum
(FWHMdec) minor axis (FWHMdecmin) (G1)
66- 70 F5.1 mJy F3mm The core-integrated 3 mm flux (Fint3mm)
72- 75 F4.1 mJy e_F3mm Mean error on F3mm (Fint3mm_error) (G2)
77- 81 F5.1 mJy/beam Fp3mm The core-peak flux (Fp3mm)
83- 85 F3.1 mJy/beam e_Fp3mm Mean error on (Fp3mm_error) (G2)
87- 89 F3.1 10-2pc Rcore The radii of the cores (Rcore) (G3)
91- 93 F3.1 10-2pc E_Rcore Upper uncertainty of Rcore (E_Rcore) (G4)
95- 97 F3.1 10-2pc e_Rcore Lower uncertainty of Rcore (e_Rcore) (G4)
99-101 I3 --- Nline Number of lines detected in the two
line-scan spectal windows 7 and 8 of
Atacama Compact Array (Nline)
103-105 F3.1 [Msun] logMcore Logarithm of the core mass calculated
with equation B1 (appendix B) (Mcore)
107-109 F3.1 [Msun] E_logMcore Upper uncertainty of logMcore (E_logMcore)
(G4)
111-113 F3.1 [Msun] e_logMcore Lower uncertainty of logMcore (e_logMcore)
(G4)
115-117 F3.1 [cm-3] logncore Logarithm of the number density of the core
calculated with equation B2 (appendix B)
(ncore)
119-121 F3.1 [cm-3] E_logncore Upper uncertainty of logncore (E_logncore)
(G4)
123-125 F3.1 [cm-3] e_logncore Lower uncertainty of logMcore (e_logMcore)
(G4)
127-131 F5.1 g/cm2 Sigmacore The core mass surface density (Sigmacore)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Clump Name Clump
13- 29 A17 --- Core Galactic Name core
31- 34 F4.1 kpc D Distance
36- 38 F3.1 kpc E_D Upper uncertainty of D (E_D)
40- 42 F3.1 kpc e_D Lower uncertainty of D (e_D)
44- 46 F3.1 arcsec MajAxis Full-Width at Half-Maximum (FWHM) major
axis (FWHMmaj) (G1)
48- 50 F3.1 arcsec MinAxis Full-Width at Half-Maximum (FWHM) minor
axis (FWHMmin) (G1)
52- 56 F5.1 deg PA Position Angle (PA)
58- 60 F3.1 arcsec MajAxisdec Deconvolved Full-Width at Half-Maximum
(FWHMdec) major axis (FWHMdecmaj) (G1)
62- 64 F3.1 arcsec MinAxisdec Deconvolved Full-Width at Half-Maximum
(FWHMdec) minor axis (FWHMdecmin) (G1)
66- 70 F5.1 mJy F3mm The core-integrated 3 mm flux (Fint3mm)
72- 75 F4.1 mJy e_F3mm Mean error on F3mm (Fint3mm_error) (G2)
77- 80 F4.1 mJy/beam Fp3mm The core-peak flux (Fp3mm)
82- 84 F3.1 mJy/beam e_Fp3mm Mean error on (Fp3mm_error) (G2)
86- 89 F4.1 10-2pc Rcore The radii of the cores (Rcore) (G3)
91- 93 F3.1 10-2pc E_Rcore Upper uncertainty of Rcore (E_Rcore) (G4)
95- 97 F3.1 10-2pc e_Rcore Lower uncertainty of Rcore (e_Rcore) (G4)
99-100 I2 --- Nline Number of lines detected in the two
line-scan spectal windows 7 and 8 of
Atacama Compact Array (Nline)
102-104 F3.1 [Msun] logMcore Logarithm of the core mass calculated
with equation B1 (appendix B) (Mcore)
106-108 F3.1 [Msun] E_logMcore Upper uncertainty of logMcore (E_logMcore)
(G4)
110-112 F3.1 [Msun] e_logMcore Lower uncertainty of logMcore (e_logMcore)
(G4)
114-116 F3.1 [cm-3] logncore Logarithm of the number density of the core
calculated with equation B2 (appendix B)
(ncore)
118-120 F3.1 [cm-3] E_logncore Upper uncertainty of logncore
(E_logncore) (G4)
122-124 F3.1 [cm-3] e_logncore Lower uncertainty of logMcore
(e_logMcore) (G4)
126-129 F4.1 g/cm2 Sigmacore The core mass surface density (Sigmacore)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Clump Name Clump
13- 29 A17 --- Core Galactic Name core
31- 34 F4.1 kpc D Distance
36- 38 F3.1 kpc E_D Upper uncertainty of D (E_D)
40- 42 F3.1 kpc e_D Lower uncertainty of D (e_D)
44- 47 F4.1 arcsec MajAxis Full-Width at Half-Maximum (FWHM)
major axis (FWHMmaj) (G1)
49- 52 F4.1 arcsec MinAxis Full-Width at Half-Maximum (FWHM)
minor axis (FWHMmin) (G1)
54- 58 F5.1 deg PA Position Angle (PA)
60- 63 F4.1 arcsec MajAxisdec Deconvolved Full-Width at Half-Maximum
(FWHMdec) major axis (FWHMdecmaj) (G1)
65- 68 F4.1 arcsec MinAxisdec Deconvolved Full-Width at Half-Maximum
(FWHMdec) minor axis (FWHMdecmin) (G1)
70- 75 F6.1 mJy F3mm The core-integrated 3 mm flux (Fint3mm)
77- 80 F4.1 mJy e_F3mm Mean error on F3mm (Fint3mm_error) (G2)
82- 86 F5.1 mJy/beam Fp3mm The core-peak flux (Fp3mm)
88- 91 F4.1 mJy/beam e_Fp3mm Mean error on (Fp3mm_error) (G2)
93- 96 F4.1 10-2pc Rcore The radii of the cores (Rcore) (G3)
98-100 F3.1 10-2pc E_Rcore Upper uncertainty of Rcore (E_Rcore) (G4)
102-104 F3.1 10-2pc e_Rcore Lower uncertainty of Rcore (e_Rcore) (G4)
106-109 F4.1 [Msun] logMcore Logarithm of the core mass calculated
with equation B1 (appendix B) (Mcore)
111-113 F3.1 [Msun] E_logMcore Upper uncertainty of logMcore (E_logMcore)
(G4)
115-117 F3.1 [Msun] e_logMcore Lower uncertainty of logMcore (e_logMcore)
(G4)
119-121 F3.1 [cm-3] logncore Logarithm of the number density of the core
calculated with equation B2 (appendix B)
(ncore)
123-125 F3.1 [cm-3] E_logncore Upper uncertainty of logncore (E_logncore)
(G4)
127-129 F3.1 [cm-3] e_logncore Lower uncertainty of logMcore (e_logMcore)
(G4)
131-135 F5.1 g/cm2 Sigmacore The core mass surface density (Sigmacore)
--------------------------------------------------------------------------------
Global notes:
Note (G1): FWHM is the measured core size, while FWHMdec is the corresponding
deconvolved size.
Note (G2): The erros on the fluxes come from the 2D Gaussian fitting in the
core extraction.
Note (G3): Rcore follows the form of Reff/3600 * pi/180 * D, where Reff is the
effective radius equal to sqrt(FWHMdec)/2, and D is the distance
of the core. Calculated assuming the same distance as that of their
natal clumps (Liu et al. 2020MNRAS.496.2790L 2020MNRAS.496.2790L, Cat. J/MNRAS/496/2790).
Note (G4): The errors mainly result from the distance
uncertainties.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Liu et al, Paper I 2020MNRAS.496.2790L 2020MNRAS.496.2790L, Cat. J/MNRAS/496/2790
Liu et al, Paper II 2020MNRAS.496.2821L 2020MNRAS.496.2821L, Cat. J/MNRAS/496/2821
(End) Luc Trabelsi [CDS] 31-May-2024