J/AJ/167/220 207 molecular clouds distance measurements; MWISP (Zhang+, 2024)
The Multilayer Nature of Molecular Gas toward the Cygnus Region.
Zhang S., Su Y., Chen X., Fang M., Yan Q.-Z., Zhang S., Sun Y., Wang X.,
Feng H., Ma Y., Zhang M., Zhuang Zi, Zhou X., Chen Z., Yang Ji
<Astron. J., 167, 220 (2024)>
=2024AJ....167..220Z 2024AJ....167..220Z
ADC_Keywords: Millimetric/submm sources; Molecular clouds; Interstellar medium
Keywords: Interstellar medium ; Distance measure ; Molecular clouds ;
Molecular gas
Abstract:
We study the physical properties and 3D distribution of molecular
clouds (MCs) toward the Cygnus region using the MWISP CO survey and
Gaia DR3 data. Based on Gaussian decomposition and clustering for 13CO
lines, over 70% of the fluxes are recovered. With the identification
result of 13CO structures, two models are designed to measure the
distances of the molecular gas in velocity crowding regions. The
distances of more than 200 large 13CO structures are obtained toward
the 150 deg2 region. Additionally, tens of the identified MC
structures coincide well with masers and/or intense mid-IR emission.
We find multiple gas layers toward the region: (1) the extensive gas
structures composing the Cygnus Rift from 700pc to 1kpc across the
whole region; (2) the ∼1.3kpc gas layer mainly in the Cygnus X South
region; and (3) the 1.5kpc dense filament at the Cygnus X North region
and many cometary clouds shaped by Cygnus OB2. We also note that the
spatial distribution of young stellar object candidates is generally
consistent with the molecular gas structures. The total molecular mass
of the Cygnus region is estimated to be ∼2.7x106M☉ assuming an
X-factor ratio XCO=(2x1020cm-2Kkms-1)-1. The foreground
Cygnus Rift contributes ∼25% of the molecular mass in the whole
region. Our work presents a new 3D view of the MCs' distribution
toward the Cygnus X region, as well as the exact molecular gas mass
distribution in the foreground Cygnus Rift.
Description:
The MWISP project is an ongoing CO survey by using the PMO 13.7m
millimeter-wavelength telescope at Delingha, China. The survey
observes 12CO, 13CO, and C18O simultaneously toward the northern
Galactic plane.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 91 207 Parameters of 207 Molecular Clouds (MC) structures
with distance measurement
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See also:
II/196 : Vilnius Photometry in two Nebulae (Straizys et al., 1993)
VIII/39 : Composite CO Survey of the Milky Way (Dame+ 1987)
J/AJ/101/1408 : Massive stars in Cyg OB2. (Massey+ 1991)
J/A+A/241/551 : Radio continuum in Cygnus X region (Wendker+ 1991)
J/A+A/476/1243 : Millimeter continuum mapping of Cygnus X (Motte+, 2007)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJ/720/679 : Optical spectroscopy in Cygnus X region (Beerer+, 2010)
J/A+A/554/A55 : C18O(1-0) and N2H+(1-0) in L1495/B213 (Hacar+, 2013)
J/ApJS/212/1 : The WISE catalog of Galactic HII regions (Anderson+, 2014)
J/AJ/147/46 : Properties of clumps in the NAN complex (Zhang+, 2014)
J/MNRAS/449/741 : The massive star population of Cygnus OB2 (Wright+, 2015)
J/A+A/601/A124 : Clouds in SEDIGISM science demonstr. field (Schuller+, 2017)
J/A+A/610/A12 : Clustering the Orion B giant molecular cloud (Bron+, 2018)
J/MNRAS/484/1838 : Spatial substructure of Cygnus OB2 (Berlanas+, 2019)
J/MNRAS/483/4291 : Properties of JCMT CO(3-2) molecular clouds (Colombo+, 2019)
J/ApJ/885/131 : ∼200 high-mass SFR plx & proper motion VLBI (Reid+, 2019)
J/ApJ/883/156 : Nobeyama 45m Cygnus-X CO. II. C180 clumps (Takekoshi+, 2019)
J/A+A/641/A79 : FEDReD. Extinction map 2MASS and Gaia DR2 (Hottier+, 2020)
J/A+A/633/A51 : Distances to molecular clouds in SFR (Zucker+, 2020)
J/MNRAS/500/3027 : The SEDIGISM survey: molecular clouds (Duarte-Cabral+, 2021)
J/A+A/645/A27 : Orion B in 18 molecular tracers maps (Gratier+, 2021)
J/ApJS/254/3 : CO obs. of molecular clouds in the MW midplane (Ma+, 2021)
J/A+A/655/A64 : Galactic CO maps (Mertsch+, 2021)
J/MNRAS/502/6080 : New members of Cygnus OB2 from Gaia DR2 (Orellana+, 2021)
J/MNRAS/508/2370 : Revisiting the Cygnus OB associations (Quintana+, 2021)
J/ApJ/922/8 : Molecular cloud distances from CO & Gaia data (Yan+, 2021)
J/A+A/665/A63 : DR20 integrated intensity maps (Beuther+, 2022)
J/MNRAS/515/687 : Large-scale expansion of OB stars Cygnus (Quintana+, 2022)
J/ApJS/261/37 : 13CO emission in MWISP 12CO molecular clouds (Yuan+, 2022)
J/ApJS/271/25 : The first LHAASO catalog of gamma-ray sources (Cao+, 2024)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [1/207] Cloud identifier in this work
5- 9 F5.2 deg GLON [72/87] Galactic longitude; see Equ. 3 (1)
11- 15 F5.2 deg GLAT [-5/4] Galactic latitude; see Equ. 4 (1)
17- 21 F5.1 km/s vLSR [-30.4/15.1] Local Standard of Rest velocity ;
see Equ. 8 (1)
23- 25 F3.1 km/s sigmav [0.5/3.1] Intensity weighted velocity dispersion;
see Equ. 9
27- 30 F4.1 pc Rad [0.8/14.1] Physical size; see Equ. 17
32- 35 I4 pc dA [514/2478]? Model A median distance
37- 39 I3 pc E_dA [4/115]? The 84% uncertainty in dA (2)
41- 42 I2 pc e_dA [3/91]? The 16% uncertainty in dA (2)
44- 46 I3 pc Sys-dA [25/123]? The 5% system uncertainty of Gaia data
in dA
48- 51 I4 pc dB [535/2399]? Model B median distance
53- 55 I3 pc E_dB [3/127]? The 84% uncertainty in dB (2)
57- 59 I3 pc e_dB [5/117]? The 16% uncertainty in dB (2)
61- 63 I3 pc Sys-dB [26/119]? The 5% system uncertainty of Gaia data
in dB
65- 72 E8.2 /cm2 Nmean [6.04e+20/1.27e+22] Mean column density (3)
74- 78 I5 Msun MassLTE [40/49490] LTE mass (4)
80- 84 I5 Msun MassXf [70/68310] Xfactor mass (5)
86- 89 F4.1 --- alpha [0.6/31.7] Virial parameter of 13CO traced cloud;
see Equ. 21
91- 91 A1 --- Model Adopted model that gave more accurate distance
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Note (1): Of cloud center weighted by intensity.
Note (2): Uncertainties represent the value in MCMC samples of cloud distance.
Note (3): Based on LTE, which is calculated by Equ. (13) and (16).
Note (4): Derived from 13CO emission with determined distance, which is
calculated by column density of 13CO emission, see Equ. (13) and (18).
Note (5): Mass calculated by 12CO emission with determined distance, in a
13CO traced cloud boundary. The CO-to-H2 Conversion Factor adopts
XCO=2*1e20cm-2/(K*km/s).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 19-Aug-2024