J/ApJ/922/8 Molecular cloud distances from CO & Gaia data (Yan+, 2021)
Improved measurements of molecular cloud distances based on global search.
Yan Q.-Z., Yang Ji, Su Y., Sun Y., Xu Ye, Wang H., Zhou X., Wang C.
<Astrophys. J., 922, 8 (2021)>
=2021ApJ...922....8Y 2021ApJ...922....8Y
ADC_Keywords: Molecular clouds; Interstellar medium; Carbon monoxide;
Extinction; Stars, distances; Space velocities
Keywords: Molecular clouds ; Interstellar medium ; Interstellar molecules ;
Interstellar dust extinction ; Distance measure ; Stellar distance
Abstract:
The principle of the background-eliminated extinction-parallax (BEEP)
method is examining the extinction difference between on- and
off-cloud regions to reveal the extinction jump caused by molecular
clouds, thereby revealing the distance in complex dust environments.
The BEEP method requires high-quality images of molecular clouds and
high-precision stellar parallaxes and extinction data, which can be
provided by the Milky Way Imaging Scroll Painting (MWISP) CO survey
and the Gaia DR2 catalog, as well as supplementary AV extinction data.
In this work, the BEEP method is further improved (BEEP-II) to
measure molecular cloud distances in a global search manner. Applying
the BEEP-II method to three regions mapped by the MWISP CO survey, we
collectively measured 238 distances for 234 molecular clouds. Compared
with previous BEEP results, the BEEP-II method measures distances
efficiently, particularly for those molecular clouds with large
angular size or in complicated environments, making it suitable for
distance measurements of molecular clouds in large samples.
Description:
The CO data are part of the Milky Way Imaging Scroll Painting (MWISP)
CO survey (Su+ 2019ApJS..240....9S 2019ApJS..240....9S) conducted with the Purple Mountain
Observatory (PMO) 13.7m millimeter telescope. The angular and velocity
resolutions of the 12CO maps are approximately 49" and 0.2km/s,
respectively. CO maps are regridded into pixels of 30", corresponding
to an rms noise of about 0.49K.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 130 238 Distances to molecular clouds
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Description of file:
harvardDisTable_Q123.fit.gz is the original FITS file downloaded at:
http://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/0J76GM
See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/349 : StarHorse, Gaia DR2 photo-astrometric distances (Anders+, 2019)
II/360 : Gaia DR2 x AllWISE catalogue (Marton+, 2019)
J/ApJ/834/57 : MW molecular clouds from 12CO (Miville-Deschenes+, 2017)
J/ApJ/867/151 : YSOs in Gould Belt regions with Gaia-DR2 data (Dzib+, 2018)
J/A+A/620/A172 : Solar neighbourhood young stars 3D mapping (Zari+, 2018)
J/MNRAS/483/4291 : Properties of JCMT CO(3-2) molecular clouds (Colombo+, 2019)
J/ApJ/885/131 : High-mass SFR plx & proper motion with VLBI (Reid+, 2019)
J/A+A/638/A85 : Taurus 3D view with Gaia & Herschel (Roccatagliata+, 2020)
J/A+A/633/A51 : Distances to molecular clouds in SFR (Zucker+, 2020)
J/ApJ/910/131 : Molecular gas distribution from MWISP CO survey (Su+, 2021)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Cloud name (GLLL.l+BB.b) (cloudName)
13- 24 F12.8 deg GLON [26.9/219.7] Galactic longitude (l)
26- 36 F11.8 deg GLAT [-4.9/4.7] Galactic latitude (b)
38- 45 F8.4 km.s-1 Vlsr [-47/34.5] LSR velocity
47- 53 F7.4 deg2 Area [0.016/17] Angular area
55- 58 I4 pc Dist [278/2624] Gaia DR2 distance (distance)
60- 62 I3 pc e_Dist [8/266] Dist uncertainty (distanceError) (1)
64- 75 F12.8 deg GLONC [26.5/219.7] Region center Galactic longitude
(centerL) (2)
77- 87 F11.8 deg GLATC [-5.1/4.7] Region center Galactic latitude
(centerB) (2)
89- 90 I2 deg Rad [5/15] Radius (radius)
92 I1 K.km.s-1 COcut [2/5] CO cut (3)
94- 97 I4 pc DCut [500/3000] Distance cut (distanceCut)
99- 102 I4 --- N [13/1179] Total number of on-cloud stars
104- 114 F11.4 Msun Mass [48.7/775427]?=0 Mass (4)
116- 125 F10.4 Msun e_Mass [12.9/89209]?=0 Mass uncertainty (massError)
127- 130 A4 --- Ext Gaia DR2 extinction (AV or AG) (AVAG)
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Note (1): The distance error is the standard deviation, and the 5% systematic
error is not included.
Note (2): Circular regions that contain on- and off-cloud stars.
Note (3): The lower threshold of CO emission for on-cloud stars.
Note (4): The mass estimate only takes into account CO-bright molecular gas,
and only the distance error is considered, including the 5% systematic
error. Only molecular clouds with unique distances have masses
calculated.
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History:
Downloaded at: http://dataverse.harvard.edu/dataset.xhtml?
persistentId=doi:10.7910/DVN/0J76GM
(End) Emmanuelle Perret [CDS] 13-Mar-2023