J/A+AS/134/241 Rotation in molecular clouds (Phillips 1999)
Rotation in molecular clouds
Phillips J.P.
<Astron. Astrophys. Suppl. Ser. 134, 241 (1999)>
=1999A&AS..134..241P 1999A&AS..134..241P (SIMBAD/NED BibCode)
ADC_Keywords: Nebulae; Rotational velocities ; Morphology
Keywords: ISM: clouds - ISM:: kinematics and dynamics - ISM: molecules -
ISM: structure
Abstract:
We have investigated a broad range of evidence concerning rotation in
molecular clouds. As a consequence, we show that trends in specific
angular momentum J/M and angular velocity Ω are inconsistent
with certain models of isothermal, non-magnetic cloud rotation.
Similarly, models of rotation which invoke turbulent vorticity may
have only limited applicability to clumps and condensations. There is
evidence to favour an important role for rotation in maintaining the
stability of disks, larger cloud structures, and perhaps a large
fraction of intermediate sized clouds, whilst rotation may also be
implicated in maintaining observed departures from cloud sphericity.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 187 168 Rotational parameters of molecular clouds
notes.txt 80 74 Notes on table1.dat
refs.dat 48 110 References of table1.dat
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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- 17 A17 --- Name Name of source
18- 19 A2 --- Note Notes, see file notes.txt
21- 22 I2 h RAh ? Right ascension (1950.0)
24- 25 I2 min RAm ? Right ascension (1950.0)
27- 30 F4.1 s RAs ? Right ascension (1950.0)
32 A1 --- DE- Declination sign
33- 34 I2 deg DEd ? Declination (1950.0)
36- 37 I2 arcmin DEm ? Declination (1950.0)
39- 42 F4.1 arcsec DEs ? Declination (1950.0)
44 A1 --- l_Dist Limit flag on Dist
45- 49 F5.3 kpc Dist ? Distance to cloud
50 A1 --- u_Dist [?] Uncertainty flag on Dist
52- 57 F6.2 km/s RV ? LSR velocity of cloud
59- 63 F5.2 km/s DV ? Kinematic line width
(lower value of interval when "->")
64- 65 A2 --- --- [-> ] Indicates an interval
66- 69 F4.1 km/s DV2 ? Upper kinematic line width when interval
71 A1 --- l_Size Limit flag on Size
72- 79 E8.2 pc Size Size of cloud, over the region of maximum
velocity gradient, i.e. perpendicular to the
axis of rotation. (lower value when interval)
80- 81 A2 --- n_Size [-> ] Indicates an interval
82- 85 F4.2 pc Size2 ? Upper size of cloud when interval
87-113 A27 --- Trans Molecular transition(s) employed for the
observations
115 A1 --- L_OMEGA Limit flag on OMEGA
116-122 F7.3 10-14s-1 OMEGA Angular rotation rate
(lower value when interval)
123-124 A2 --- --- [-> ] Indicates an interval
125-129 F5.1 10-14s-1 OMEGA2 ? Upper angular rotation rate when interval
131 A1 --- l_GAMMA [~>] Limit flag on GAMMA
132-136 F5.2 --- GAMMA ? Cloud aspect ratio determined from molecular
emission contours (major axis/minor axis),
corresponding to the region of rotation
138-139 A2 --- l_Mass [≥ <] Limit flag on Mass
140-147 E8.2 solMass Mass ? Cloud mass for rotating cloud, or rotating
portion of cloud, determined (primarily)
from column density estimates.
(lower value when interval)
148-149 A2 --- --- [-> ] Indicates an interval
150-157 E8.2 solMass Mass2 ? Upper cloud mass value when interval
159-162 F4.1 solMass MassEm ? Mass of embedded stars
164-166 I3 deg THETA ? Orientation of rotation axis with respect to
the galactic plane
167-168 A2 --- --- [-> /] "->" interval; "/" two possible values
169-171 I3 deg THETA2 ? Upper orientation of rotation axis value if
interval, or second possible value
173 A1 --- OMEGAo *[YN] Relative orientations of the cloud minor
axis, and axis of rotation
174 A1 --- u_OMEGAo [?] Uncertainty flag on OMEGAo
176-179 A4 --- Type *Cloud type
181-187 A7 --- r_Name Reference(s), see file "refs.dat"
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Note on OMEGAo:
Y if OMEGA is within 30° of the minor axis,
N otherwise.
Note on Type:
MI: Intermediate cloud
MS: Isolated small cloud
ML: Large cloud
CL: Clumps
MIC: Condensation within an intermediate sized cloud
MLF: Filamentary large sized cloud
MLC: Condensation within a large sized cloud
D/R: Ring and disk
MIF: Filamentary intermediate sized cloud
MSFC: Condensation and filamentary within a small sized cloud
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Ref Reference number
5- 24 A20 --- Aut Authors' name
26- 44 A19 --- BibCode Reference in Bibcode form
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Acknowledgements: Peter Phillips
(End) Patricia Bauer [CDS] 31-Aug-1998