J/MNRAS/461/2288 Infall motions in massive star-forming regions (He+, 2016)
Properties of massive star-forming clumps with infall motions.
He Y., Zhou J., Esimbek J., Ji W., Wu G., Tang X., Komesh T., Yuan Y.,
Li D., Baan W.A.
<Mon. Not. R. Astron. Soc., 461, 2288-2308 (2016)>
=2016MNRAS.461.2288H 2016MNRAS.461.2288H (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs; Millimetric/submm sources; Spectroscopy;
Radio lines
Keywords: stars: formation - ISM: kinematics and dynamics - ISM: molecules -
radio lines: ISM
Abstract:
In this work, we aim to characterize high-mass clumps with infall
motions. We selected 327 clumps from the Millimetre Astronomy Legacy
Team 90-GHz survey, and identified 100 infall candidates. Combined
with the results of He et al. (2015, Cat. J/MNRAS/450/1926), we
obtained a sample of 732 high-mass clumps, including 231 massive
infall candidates and 501 clumps where infall is not detected. Objects
in our sample were classified as pre-stellar, proto-stellar, HII or
photodissociation region (PDR). The detection rates of the infall
candidates in the pre-stellar, proto-stellar, HII and PDR stages are
41.2 per cent, 36.6 per cent, 30.6 per cent and 12.7 per cent,
respectively. The infall candidates have a higher H2 column density
and volume density compared with the clumps where infall is not
detected at every stage. For the infall candidates, the median values
of the infall rates at the pre-stellar, proto-stellar, HII and PDR
stages are 2.6 x 10-3, 7.0x10-3, 6.5x10-3 and
5.5x10-3M☉/yr, respectively. These values indicate that infall
candidates at later evolutionary stages are still accumulating
material efficiently. It is interesting to find that both infall
candidates and clumps where infall is not detected show a clear trend
of increasing mass from the pre-stellar to proto-stellar, and to the
HII stages. The power indices of the clump mass function are
2.04±0.16 and 2.17±0.31 for the infall candidates and clumps where
infall is not detected, respectively, which agree well with the power
index of the stellar initial mass function (2.35) and the cold Planck
cores (2.0).
Description:
We selected high-mass clumps with N2H+(1-0), HNC(1-0), and
HCO+(1-0) emission lines detected simultaneously from the MALT90
survey data, i.e. with an S/N>3, and searched for infall signatures
using these three lines.
To ensure the clumps in our sample are separated, and not contaminated
by emission from an adjacent clump, each source with an angular
separation of less than 36 arcsec (the Mopra beam size at 90GHz) from
its nearest neighbour was excluded. HYX15 (He et al., 2015, Cat.
J/MNRAS/450/1926) studied 405 high-mass clumps selected from the
MALT90 survey (years 1 and 2) and identified 131 infall candidates; in
this work, 327 high-mass clumps were selected from the remaining data
from the MALT90 survey and an additional 100 infall candidates were
identified.
In total, we created a sample of 732 high-mass clumps, and identified
231 infall candidates.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 86 405 Derived clump parameters (list of He et al.,
2015, Cat. J/MNRAS/450/1926)
tablea2.dat 88 327 Derived clump parameters of the observed sources
tablea3.dat 76 327 The derived line parameters and profiles of
the observed sources
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See also:
J/MNRAS/450/1926 : Infall motions in massive star-forming regions (He+, 2015)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1 A1 --- n_Clump [*] * for infall candidates (G1)
2- 15 A14 --- Clump Clump name (GLLL.lll+B.bbb) (G2)
17- 21 F5.2 Jy/beam Fpeak Peak submillimetre emission
23- 28 F6.2 Jy Fint Integrated submillimetre emission
30- 33 F4.1 K Tdust Dust temperature
35- 39 F5.2 kpc Dist ?=- Heliocentric distance
41- 45 F5.2 pc Reff ?=- Effective physical radius
47- 50 F4.2 --- AR Aspect ratio
52- 56 F5.2 [cm-2] logNH2 H2 column density
58- 61 F4.2 [Msun] logMclump ?=- Clump mass derived from the integrated
870um emission
63- 66 F4.2 [Msun] logMVir ?=- Virial mass
68- 72 F5.2 10+4cm-3 VDens ?=- Volume density
74- 86 A13 --- Class Spitzer classification
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- n_Clump [*] * for infall candidates (G1)
2- 15 A14 --- Clump Clump name (GLLL.lll+B.bbb) (G2)
17- 21 F5.2 Jy/beam Fpeak Peak submillimetre emission
23- 28 F6.2 Jy Fint Integrated submillimetre emission
30- 33 F4.1 K Tdust Dust temperature
35- 39 F5.2 kpc Dist ?=- Heliocentric distance
41- 42 I2 --- r_Dist ?=- Distance reference (3)
44- 47 F4.2 pc Reff ?=- Effective physical radius
49- 52 F4.2 --- AR Aspect ratio
54- 58 F5.2 [cm-2] logNH2 H2 column density
60- 63 F4.2 [Msun] logMclump ?=- Clump mass derived from the
integrated 870um emission
65- 68 F4.2 [Msun] logMvirial ?=- Virial mass
70- 74 F5.2 10+4cm-3 VDens ?=- Volume density
76- 88 A13 --- Class Spitzer classification
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Note (3): References as follows:
1 = Faundez et al. (2004, Cat. J/A+A/426/97)
2 = Hill et al. (2005, Cat. J/MNRAS/363/405)
3 = Urquhart et al. (2012, Cat. J/MNRAS/420/1656)
4 = Morales et al. (2013, Cat. J/A+A/560/A76)
5 = Chen et al. (2013, Cat. J/ApJS/206/9)
6 = Urquhart et al. (2013, Cat. J/MNRAS/431/1752)
7 = Ellsworth-Bowers et al. (2013, Cat. J/ApJ/770/39)
8 = Ragan, Henning & Beuther (2013A&A...559A..79R 2013A&A...559A..79R)
9 = Sanchez-Monge et al. (2013, Cat. J/A+A/550/A21)
10 = Lumsden et al. (2013, Cat. J/ApJS/208/11)
11 = Vasyunina et al. (2014, Cat. J/ApJ/780/85)
12 = Urquhart et al. (2014, Cat. J/MNRAS/437/1791)
13 = Urquhart et al. (2014, Cat. J/MNRAS/443/1555)
14 = Anderson et al. (2014, Cat. J/ApJS/212/1)
15 = Giannetti et al. (2014, Cat. J/A+A/570/A65)
16 = Traficante et al. (2015, Cat. J/MNRAS/451/3089)
17 = IRDC
18 = tangential point
19 = this paper
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1 A1 --- n_Clump [*] * indicates infall candidates (G1)
2- 15 A14 --- Clump Clump name (G2)
17- 23 F7.2 km/s VHCO+ Peak velocity of HCO+(1-0)
25- 27 F3.2 km/s e_VHCO+ rms uncertainty on VHCO+
29- 35 F7.2 km/s VHNC Peak velocity of HNC(1-0)
37- 39 F3.2 km/s e_VHNC rms uncertainty on VHNC
41- 47 F7.2 km/s VN2H+ Peak velocity of N2H+(1-0)
49- 51 F3.2 km/s e_VN2H+ rms uncertainty on VN2H
53- 56 F4.2 km/s DVN2H+ FWHM of N2H+(1-0)
58- 60 F3.2 km/s e_DVN2H+ rms uncertainty on DVN2H+
62- 66 F5.2 --- dvHCO+ Asymmetry of HCO+(1-0)
68- 72 F5.2 --- dvHNC Asymmetry of HNC(1-0)
74 A1 --- PHCO+ [BRN] Profile of HCO+(1-0) (3)
75 A1 --- --- [,]
76 A1 --- PHNC [BRN] Profile of HNC(1-0) (3)
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Note (3): Profile is judged from our HCO+(1-0) and HNC(1-0) as follows:
B = blue profile
R = red profile
N = neither blue nor red
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Global notes:
Note (G1): An * indicates infall candidates.
Note (G2): Sources are named by galactic coordinates of ATLASGAL sources.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 04-Dec-2017