J/ApJ/699/1153 Kinematic distances to GRS molecular clouds (Roman-Duval+, 2009)
Kinematic distances to molecular clouds identified in the Galactic Ring Survey.
Roman-Duval J., Jackson J.M., Heyer M., Johnson A., Rathborne J., Shah R.,
Simon R.
<Astrophys. J., 699, 1153-1170 (2009)>
=2009ApJ...699.1153R 2009ApJ...699.1153R
ADC_Keywords: Molecular clouds ; Interstellar medium ; Radio continuum
Keywords: Galaxy: kinematics and dynamics - Galaxy: structure - H II regions -
ISM: clouds - molecular data
Abstract:
Kinematic distances to 750 molecular clouds identified in the
13COJ=1-0 Boston University-Five College Radio Astronomy Observatory
Galactic Ring Survey (GRS) are derived assuming the Clemens rotation
curve of the Galaxy. The kinematic distance ambiguity is resolved by
examining the presence of HI self-absorption toward the 13CO
emission peak of each cloud using the Very Large Array Galactic Plane
Survey. We also identify 21cm continuum sources embedded in the GRS
clouds in order to use absorption features in the HI 21cm continuum to
distinguish between near and far kinematic distances. The Galactic
distribution of GRS clouds is consistent with a four-arm model of the
Milky Way. The locations of the Scutum-Crux and Perseus arms traced by
GRS clouds match star-count data from the Galactic Legacy Infrared
Mid-Plane Survey Extraordinaire star-count data. We conclude that
molecular clouds must form in spiral arms and be short-lived
(lifetimes <107yr) in order to explain the absence of massive,
13CO bright molecular clouds in the interarm space.
Description:
Our sample contains molecular clouds that were identified by their
13CO(J=1-0) emission in the BU-FCRAO GRS (Jackson et al.
2006ApJS..163..145J 2006ApJS..163..145J). The GRS was conducted using the Five College
Radio Astronomy Observatory (FCRAO) 14m telescope in Salem, MA,
between 1998 and 2005.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 66 752 Kinematic distances to molecular clouds in the
GRS using HI self-absorption and 21cm continuum
absorption
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See also:
J/ApJS/182/131 : Molecular clouds and clumps in the GRS (Rathborne+, 2009)
J/ApJ/699/1092 : Galactic molecular clouds (SRBY) (Heyer+, 2009)
J/ApJ/626/887 : HI clouds in Southern Galactic Plane Survey (Kavars+, 2005)
J/A+A/327/325 : Distances of molecular cloud (May+, 1997)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [GRSMC]
7- 19 A13 --- GRSMC Galactic Ring Survey (GRS) Molecular Cloud
identification (G0LL.ll+0B.bb) (1)
21- 25 F5.2 deg GLON Galactic longitude
27- 31 F5.2 deg GLAT Galactic latitude
33- 38 F6.2 km/s Vlsr Local Standard of Rest radial velocity
40- 43 F4.2 deg dLon Spatial FWHM of the cloud along Galactic
longitude
45- 48 F4.2 deg dLat Spatial FWHM of the cloud along Galactic
latitude
50- 53 F4.2 km/s DelV FWHM velocity dispersion
55- 59 F5.2 kpc Dist Kinematic distance to the cloud
61- 64 F4.2 10+4K.km/s/pc2 LCO The CO luminosity
66 A1 --- 21cm? [y ] A 21cm continuum source?
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Note (1): From Rathborne et al. (2009, Cat. J/ApJS/182/131;
in Simbad).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-Jul-2011