J/A+A/679/A123 SiO J=1-0 emission toward massive SFRs (Kim+, 2023)
A survey of SiO J = 1 - 0 emission toward massive star-forming regions.
Kim W.-J., Urquhart J.S., V.S.Veena, Fuller G.A., Schilke P., Kim K-T
<Astron. Astrophys. 679, A123 (2023)>
=2023A&A...679A.123K 2023A&A...679A.123K (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Star Forming Region ; H II regions ; Molecular clouds ;
Radio lines
Keywords: astrochemistry - surveys - ISM: clouds - stars: formation
Abstract:
The application of silicon monoxide (SiO) as a shock tracer arises
from its propensity to occur in the gas phase as a result of
shock-induced phenomena, including outflow activity and interactions
between molecular clouds and expanding HII regions or supernova
remnants. Here we search for indications of shocks toward 366 massive
star-forming regions by observing the ground rotational transition of
SiO (v=0, J=1-0) at 43GHz with the Korean VLBI Network (KVN)
21m telescopes to extend our understanding on the origins of SiO in
star-forming regions.
We analyze the thermal SiO 1-0 emission and compare the properties of
SiO emission with the physical parameters of associated massive dense
clumps as well as 22GHz H2O and Class I 44GHz CH3OH maser
emission.
We detect SiO emission toward 104 regions which consist of 57 IRDCs,
21 HMPOs, and 26 UCHIIs. Out of 104 sources, 71 and 80 sources have
22GHz H2O and 44GHz Class I CH3OH maser counterparts,
respectively. The determined median SiO column density, N(SiO), and
abundance, X(SiO), relative to N(H2) are 8.12x1012cm-2 and
1.28x10-10, respectively. These values are similar to those obtained
toward other star-forming regions and also consistent with predicted
values from shock models with low-velocity shocks (≲10-15km/s). For
sources with dust temperatures (Tdust)≲20K, we find that N(SiO) and
X(SiO) derived with the J=1-0 transition are a factor ∼3 larger than
those from the previous studies obtained with SiO 2-1. While the
X(SiO) does not exhibit any strong correlation with the evolutionary
stages of their host clumps, LSiO is highly correlated with dust
clump mass, and LSiO/Lbol also has a strong negative correlation
with Tdust. This shows that colder and younger clumps have high
LSiO/Lbol suggestive of an evolutionary trend. This trend is not
due to excess emission at higher velocities, such as SiO wing
features, as the colder sources with high LSiO/Lbol ratios lack
wing features. Comparing with H2O and Class I CH3OH masers, we
find a significant correlation between LSiO/Lbol and
LCH3OH/Lbol ratios, whereas no similar correlation is seen for
the H2O maser emission. This suggests a similar origin for the SiO
and Class I CH3OH emission in these sources.
We demonstrate that in cold regions SiO J=1-0 may be a better tracer
of shocks than higher J transition of SiO. Lower Tdust (and so
probably. less globally evolved) sources appear to have higher LSiO
relative to their Lbol. The SiO 1-0 emission toward infrared dark
sources (Tdust≲20K), which do not contain identified outflow
sources, may be related to other mechanisms producing low-velocity
shocks (5-15km/s) for example, arising from cloud-cloud collisions,
shocks triggered by expanding HII regions, global infall, or
converging flows.
Description:
List of the observed sources, Gaussian fit parameters of SiO J=1-0
lines, derived SiO column density, SiO abundance, and physical
parameters of associated dust clumps as well as luminosities of H2O
and CH3OH masers.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 94 367 List of observed sources
table3.dat 71 125 Line parameters of SiO J=1-0
table4.dat 88 104 N(SiO), X(SiO), physical parameters of dust
clumps, L(H2O), and L(CH3OH)
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See also:
J/MNRAS/473/1059 : Galactic clump properties complete sample (Urquhart+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Source name
20- 21 I2 h RAh Right ascension (J2000)
23- 24 I2 min RAm Right ascension (J2000)
26- 27 I2 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 37 I2 arcsec DEs Declination (J2000)
39- 43 F5.1 km/s Vsys Systemic velocity
45 A1 --- SiO [Y/N] SiO 1-0 detection
47- 49 A3 --- n_SiO [abcde, ] Note (1)
52 A1 --- H2O [Y/N] H2O maser detection
54 A1 --- CH3OH [Y/N] CH3OH maser detection
56- 60 A5 --- Type Selected category
62- 75 A14 --- ATLASGAL ATLASGAL name (LLL.lll+BBB.bbb)
77- 94 A18 --- Class ATLASGAL classification (2)
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Note (1): Notes as follows:
a = indicates wing features in SiO 1-0 emission
b = means SiO wing candidates for cases with a SiO FWHM≥8km/s
c = indicates SiO wings in the 2-1 transition,
d = is for the cases that there are no wings in 2-1 transition but a
broad Gaussian component has a FWHM line width ≥8km/s
e = marks for sources without any sign of wing features in either
1-0 or 2-1 transitions.
Note (2): (*) indicates UCHII sources without ATLASGAL classification.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq ID number
5- 22 A18 --- Name Source name
24 I1 --- Comp Gaussian fitted component
26- 30 F5.3 K.km/s int(Tmbdv) Velocity integrated intensity
32- 36 F5.3 K.km/s e_int(Tmbdv) Uncertainty on velocity integrated intensity
38- 43 F6.2 km/s Vpeak Peak velocity
45- 48 F4.2 km/s e_Vpeak Uncertainty on velocity
50- 54 F5.2 km/s FWHM FWHM line width
56- 59 F4.2 km/s e_FWHM Uncertainty on FWHM line width
61- 65 F5.3 K Tmb Peak intensity
67- 71 F5.2 mK rms rms
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Source Name
20- 27 E8.3 cm-2 N(SiO) ?=- Column density of SiO
29- 34 F6.3 [cm-2] log(N(H2))a ?=- Column density of H2 (ATLASGAL)
36- 41 F6.3 [cm-2] log(N(H2))b ?=- Column density of H2 (Hi-GAL PPMAP)
43- 50 E8.3 --- X(SiO) ?=- Abundance of SiO
52- 55 F4.1 kpc Dist ?=- Source distance
57- 60 F4.1 K Tdust ?=- Dust temperature
62- 66 F5.3 [Lsun] log(Lbol) ?=- Bolometric luminosity
68- 72 F5.3 [Msun] log(Mclump) ?=- Dust clump mass
74- 80 E7.3 Lsun L(H2O) ?=- H2O maser luminosity
82- 88 E7.3 Lsun L(CH3OH) ?=- CH3OH maser luminosity
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Acknowledgements:
Won-Ju Kim, wonjukim(at)ph1.uni-koeln.de
(End) Won-Ju Kim [UzK, Germany], Patricia Vannier [CDS] 04-Oct-2023