J/other/RAA/24.K5018 Properties of 13CO structures (Feng+, 2024)
Revisiting the Velocity Dispersion-Size Relation in Molecular Cloud Structures.
Feng H., Chen Z., Jiang Z., Ma Y., Yang Y., Yu S., Ge D., Zhou W., Du F.,
Wang C., ZhanG S., Su Y., Yang J.
<Res. Astron. Astrophys., 24, 115018 (2024)>
=2024RAA....24k5018F 2024RAA....24k5018F (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Interstellar medium ; Radio lines ; Carbon monoxide
Keywords: ISM: structure - ISM: kinematics and dynamics - radio lines: ISM
Abstract:
Structures in molecular ISM are observed to follow a power-law
relation between the velocity dispersion and spatial size, known as
Larson's first relation, which is often attributed to the turbulent
nature of molecular ISM and imprints the dynamics of molecular cloud
structures. Using the 13CO (J=1-0) data from the Milky Way Imaging
Scroll Painting survey, we built a sample with 360 structures having
relatively accurate distances obtained from either the reddened
background stars with Gaia parallaxes or associated maser parallaxes,
spanning from 0.4 to ∼15kpc. Using this sample and about 0.3 million
pixels, we analyzed the correlations between velocity dispersion,
surface/column density, and spatial scales. Our structure-wise results
show power-law indices smaller than 0.5 in both the σv-Reff
and σv-Reff.{SIGMA} relations. In the pixel-wise results, the
σpixv is statistically scaling with the beam physical size
(Rs={THETA}D/2) in form of σpixv∝Rs0.43±0.03.
Meanwhile, svpix in the inner Galaxy is statistically larger than the
outer side. We also analyzed correlations between σpixv and
the H2 column density N(H2), finding that σpixv stops
increasing with N(H2) after ≳1022cm-2. The structures with and
without high-column-density (>1022cm-2) pixels show different
σpixv∝N(H2)xi relations, where the mean (std) xi
values are 0.38 (0.14) and 0.62 (0.27), respectively.
Description:
In this work, we extract 13CO structures from the data cubes of the
Milky Way Imaging Scroll Painting (MWISP) survey to explore the
velocity dispersion-size relation. Y. Su et al.
(2019ApJS..240....9S 2019ApJS..240....9S) have given a detailed description of the MWISP
survey, and a preliminary noise analysis has been performed by J.-J.
Cai et al. (2021RAA....21..304C 2021RAA....21..304C). We summarize the major
characteristics of the MWISP CO data here: (a) The observations are
taken in position-switch On-The-Fly mode with half power beam widths
of ∼49" for 12CO (J=1-0), ∼52" for 13CO and C18O (J=1-0). (b)
The data are gridded into 30"x30" pixels. (c) At channel widths of
0.16, 0.17 and 0.17km/s, the typical rms noise levels, σrms,
are ∼0.5, ∼0.3 and ∼0.3K for 12CO, 13CO, and C18O, respectively.
Table 1 contains properties of the identified 13CO structures.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 238 360 Properties of the identified 13CO structures
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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 [1/360] Serial No. of the cloud structure
5- 12 F8.4 deg GLON Galactic Longitude
14- 20 F7.4 deg GLAT Galactic Latitude
22- 34 F13.9 km/s VLSR Centroid velocity
36- 46 F11.9 km/s VelDisp Velocity dispersion
48- 59 F12.9 pc Reff Effective radius
61- 71 F11.9 pc e_Reff Effective radius uncertainty
73- 84 F12.8 Msun/pc2 SIGMA mass surface density
86-101 F16.9 Msun MLTE Mass of the cloud structure
103-115 F13.9 km/s VLSRA2 Centroid velocity,
derived in the N(H2) half-max isophote
117-127 F11.9 km/s VelDispA2 Velocity dispersion,
derived in the N(H2) half-max isophote
129-139 F11.9 pc ReffA2 ? Effective radius,
derived in the N(H2) half-max isophote
141-151 F11.9 pc e_ReffA2 ? Effective radius uncertainty,
derived in the N(H2) half-max isophote
153-165 F13.8 Msun/pc2 SIGMAA2 Mass surface density,
derived in the N(H2) half-max isophote
167-181 F15.9 Msun MLTEA2 ? Mass of the cloud structure,
derived in the N(H2) half-max isophote
183-194 F12.9 kpc D Heliocentric distance
197-207 F11.9 kpc e_D Heliocentric distance uncertainty,
lower value
209-219 F11.9 kpc E_D Heliocentric distance uncertainty,
upper value
221-235 A15 --- DName Name of the source for distance measurement
237-238 I2 --- r_D Reference of the source (1)
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Note (1): References as follows:
1 = Reid et al. (2019ApJ...885..131R 2019ApJ...885..131R, Cat. J/ApJ/885/131)
2 = VERA Collaboration et al. (2020PASJ...72...50V 2020PASJ...72...50V)
3 = Xu et al. (2021ApJS..253....1X 2021ApJS..253....1X)
4 = Yan et al. (2021ApJ...922....8Y 2021ApJ...922....8Y, Cat. J/ApJ/922/8)
5 = Bian et al. (2022AJ....163...54B 2022AJ....163...54B)
6 = Sakai et al. (2022PASJ...74..209S 2022PASJ...74..209S)
7 = Li et al. (2022ApJS..262...42L 2022ApJS..262...42L, Cat. J/ApJS/262/42)
8 = Mei et al. (2024A&A...685A..39M 2024A&A...685A..39M)
9 = Zhang et al. (2024AJ....167..220Z 2024AJ....167..220Z, Cat. J/AJ/167/220)
10 = Zhuang et al. (2024ApJ...966..202Z 2024ApJ...966..202Z)
11 = Bian et al. (2024AJ....167..267B 2024AJ....167..267B)
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History:
From electronic version of the journal,
https://doi.org/10.57760/sciencedb.14853
(End) Patricia Vannier [CDS] 12-Aug-2025