J/A+A/357/1001 The λ-Orionis ring in CO (Lang+ 2000)
The λ-Orionis ring in CO.
Lang W.J., Masheder M.R.W., Dame T.M., Thaddeus P.
<Astron. Astrophys. 357, 1001 (2000)>
=2000A&A...357.1001L 2000A&A...357.1001L
ADC_Keywords: Molecular clouds ; Radio lines
Keywords: ISM: clouds - Galaxy: structure - radio lines: ISM - ISM: molecules -
ISM: bubbles
Description:
The table shows clump parameters for 130 peaks in CO(J=1->0) emission
detected in the Lambda-Orionis ring in the survey of Lang et al.
(1998PASA...15...70L 1998PASA...15...70L). The clumps were isolated using the Clumpfind
algorithm of Williams et al. (1994, Cat. J/ApJ/428/693). They are
ordered and labelled according to the relative brightness of the peak
temperatures within them, so clump 1 contains the emission maximum,
but not necessarily the maximum W(CO) or largest mass.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 75 130 Clump parameters
table2.tex 101 201 LaTeX version of table 2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- LMD2000 [1/130] Clump sequential number
5- 11 F7.3 deg GLON Galactic longitude
13- 19 F7.3 deg GLAT Galactic latitude
21- 25 F5.2 km/s Vel Centroid velocity of the clump emission
27- 31 F5.2 K Tmax Maximum brightness temperature within the peak
33- 36 F4.2 pc Dl Approximate FWHM clump dimension in longitude
38- 41 F4.2 pc Db Approximate FWHM clump dimension in latitude
43- 46 F4.2 pc R Effective clump radius, R=sqrt(area/π)
48- 51 F4.2 km/s DVel Average FWHM linewidth
53- 58 F6.1 solMass MCO CO mass estimates (1)
60- 66 F7.2 solMass Mvir Virial mass estimates (2)
68- 75 A8 --- Complex Section of the ring in which the clump
is to be found (See fig. 2)
--------------------------------------------------------------------------------
Note (1): We define M(CO) as the molecular cloud mass derived
on the assumption that the velocity-integrated CO intensity, W(CO),
is directly proportional to the H2 column density. Here we use the
conversion factor:
X=N(H2)/W(CO)=1.1*1020 (molecules/cm2)/(K.km/s).
Note (2): We define the virial mass such that virial equilibrium
between kinetic energy and potential energy would be satisfied, with
Mvir=k*R*(Δv)2, where R is the effective radius of the cloud
and Δv the FWHM of the CO emission. Here k is a constant of
proportionality which depends weakly on the assumed radial density
profile of clouds. For uniform density, k=210 in the units used here.
--------------------------------------------------------------------------------
Acknowledgements: M.R.W. Masheder
(End) Patricia Bauer [CDS] 04-Sep-2000