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J/ApJS/95/457 IRAS images of nearby dark clouds (Wood+ 1994)
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IRAS images of nearby dark clouds
Wood D.O.S., Myers P.C., Daugherty D.A.
<Astrophys. J. Suppl. Ser. 95, 457 (1994)>
=1994ApJS...95..457W (SIMBAD/NED BibCode)
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ADC_Keywords: Infrared sources; Interstellar medium
Mission_Name: IRAS
Keywords: dust, extinction - infrared: ISM: continuum - ISM: molecules
Abstract:
We have investigated ~100 nearby molecular clouds using the extensive,
all-sky database of IRAS. The clouds in this study cover a wide range
of physical properties including visual extinction, size, mass, degree
of isolation, homogeneity and morphology. IRAS 100 and 60 micrometre
co-added images were used to calculate the 100 micrometre optical
depth of dust in the clouds. These images of dust optical depth
compare very well with ^12^CO and ^13^CO observations, and can be
related to H_2_ column density. From the optical depth images we
locate the edges of dark clouds and the dense cores inside them. We
have identified a total of 43 "IRAS clouds" (regions with Av>2) which
contain a total of 255 "IRAS cores" (regions with Av>4) and we catalog
their physical properties. We find that the clouds are remarkably
filamentary, and that the cores within the clouds are often
distributed along the filaments. The largest cores are usually
connected to other large cores by filaments. We have developed
selection criteria to search the IRAS Point Source Catalog for stars
that are likely to be associated with the clouds and we catalog the
IRAS sources in each cloud or core. Optically visible stars associated
with the clouds have been identified from the Herbig and Bell catalog.
From these data we characterize the physical properties of the clouds
including their star-formation efficiency.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2 43 16 Field studied
table3 97 16 *Flat-fielding and background subtraction
table4 82 43 IRAS clouds (Av > 2 mag)
table5 127 261 IRAS cores (Av > 4 mag)
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Note on table3 : This table list the coordinates of the three points and flux
values that were used to calculate the flat field, and the position where the
background was measured and the flux that was subtracted from the 100{mu}m and
60{mu}m images.
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See also:
II/125 :IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
Byte-by-byte Description of file: table2
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Field name
10- 11 I2 h RAh Center right ascension (1950)
13- 14 I2 min RAm Center right ascension (1950)
16 A1 --- DE- Center declination sign
17- 18 I2 deg DEd Center declination (1950)
20- 21 I2 arcmin DEm Center declination (1950)
23- 28 F6.2 deg GLON Galactic longitude
30- 35 F6.2 deg GLAT Galactic latitude
37- 39 F3.1 deg Dim1 Dimension
40 A1 --- --- [x]
41- 43 F3.1 deg Dim2 Dimension
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Byte-by-byte Description of file: table3
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Bytes Format Units Label Explanations
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1- 7 A7 --- Field Field name
9- 11 I3 arcmin oRA1 ? Point 1 R.A. offset (1)
13- 16 I4 arcmin oDE1 ? Point 1 Dec. offset (1)
18- 23 F6.2 MJy/sr S100um1 ? Point 1 100{mu}m flux (1)
25- 30 F6.2 MJy/sr S60um1 ? Point 1 60{mu}m flux (1)
32- 34 I3 arcmin oRA2 ? Point 2 R.A. offset (1)
36- 39 I4 arcmin oDE2 ? Point 2 Dec. offset (1)
41- 46 F6.2 MJy/sr S100um2 ? Point 2 100{mu}m flux (1)
48- 52 F5.2 MJy/sr S60um2 ? Point 2 60{mu}m flux (1)
54- 56 I3 arcmin oRA3 ? Point 3 R.A. offset (1)
58- 61 I4 arcmin oDE3 ? Point 3 Dec. offset (1)
63- 68 F6.2 MJy/sr S100um3 ? Point 3 100{mu}m flux (1)
70- 74 F5.2 MJy/sr S60um3 ? Point 3 60{mu}m flux (1)
76- 78 I3 arcmin oRAB Background subtraction R.A. offset
80- 82 I3 arcmin oDEB Background subtraction Dec. offset
84- 89 F6.2 MJy/sr S100umB Background subtraction 100{mu}m flux
91- 95 F5.2 MJy/sr S60umB Background subtraction 60{mu}m flux
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Note (1): Blank: no flat field subtraction
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Byte-by-byte Description of file: table4
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Bytes Format Units Label Explanations
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1- 5 A5 --- Cloud Cloud name (1)
7- 10 I4 pc Dist Assumed distance to the cloud
12- 13 I2 h RABh Bottom left field right ascension (1950)
15- 16 I2 min RABm Bottom left field right ascension (1950)
18- 21 F4.1 s RABs Bottom left field right ascension (1950)
23 A1 --- DEB- Bottom left field declination sign
24- 25 I2 deg DEBd Bottom left field declination (1950)
27- 28 I2 arcmin DEBm Bottom left field declination (1950)
30- 33 F4.1 arcsec DEBs Bottom left field declination (1950)
35- 36 I2 h RATh Top right field right ascension (1950)
38- 39 I2 min RATm Top right field right ascension (1950)
41- 44 F4.1 s RATs Top right field right ascension (1950)
46 A1 --- DET- Top right field declination sign
47- 48 I2 deg DETd Top right field declination (1950)
50- 51 I2 arcmin DETm Top right field declination (1950)
53- 56 F4.1 arcsec DETs Top right field declination (1950)
58- 64 F7.2 pc+2 Area Total area of the cloud
66- 68 I3 10-6 Tau100 Mean 100{mu}m optical depth
70 A1 --- l_Mass Limit flag on Mass
71- 76 I6 solMass Mass H_2_ total mass
78- 82 A5 --- Note Notes (2)
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Note (1): Name of the constellation where the cloud is located followed by a
single letter where A is the most massive cloud we identified in that
constellation, B is the second most massive and so on.
Notes (2): 1: The cloud is truncated by one or more image edges.
2: Part or all of the cloud lies in the region of overlap
between two images.
3: Cloud mass is an upper limit due to significant heating
by embedded stars.
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Byte-by-byte Description of file: table5
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Bytes Format Units Label Explanations
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1- 8 A8 --- Core Core name (1)
10- 11 I2 h RAPh Peak 100um optical depth right ascension (1950)
13- 14 I2 min RAPm Peak 100um optical depth right ascension (1950)
16- 19 F4.1 s RAPs Peak 100um optical depth right ascension (1950)
21 A1 --- DEP- Peak 100um optical depth declination sign
22- 23 I2 deg DEPd Peak 100um optical depth declination (1950)
25- 26 I2 arcmin DEPm Peak 100um optical depth declination (1950)
28- 29 I2 arcsec DEPs Peak 100um optical depth declination (1950)
30- 35 I6 10-6 TauMax Maximal optical depth in the core (in {mu}neper)
37- 39 I3 K T(TauMax) Dust temperature at the position of TauMax
41- 42 I2 h RAEh Ellipse right ascension (1950) (2)
44- 45 I2 min RAEm Ellipse right ascension (1950) (2)
47- 50 F4.1 s RAEs Ellipse right ascension (1950) (2)
52 A1 --- DEE- Ellipse declination sign (2)
53- 54 I2 deg DEEd Ellipse declination (1950) (2)
56- 57 I2 arcmin DEEm Ellipse declination (1950) (2)
59- 60 I2 arcsec DEEs Ellipse declination (1950) (2)
62- 66 F5.2 pc MajAxis Ellipse major axis (2)
68- 72 F5.2 pc MinAxis Ellipse minor axis (2)
74- 76 I3 deg PA Ellipse position angle (deg E of N) (2)
78- 85 F8.4 pc+2 Area Core area
86 A1 --- l_MassC Limit flag on MassC
87- 94 F8.1 solMass MassC Total mass of the core
96- 99 F4.1 10+21cm-2 N Mean core column density
101-102 I2 --- HD Number of associated stars from HD catalogue
104-105 I2 --- IRAS Numer of IRAS PSC associations
106 A1 --- l_Mass Limit flag on Mass
107-112 F6.2 solMass Mass Total mass of all IRAS stars associated with
the core
113 A1 --- l_Lum Limit flag on Lum
114-121 F8.1 solLum Lum Total luminosity of all IRAS stars associated
with the core
123-127 A5 --- Note Notes (3)
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Note (1): Name of the core which is the name of the parent cloud (table4)
followed by a number, 1 is the most massive core in the cloud,
2 is the next most massive core and so on.
Note (2): Parameters of an ellipse that fit to each core by eye.
Note (3): 1: The cloud is truncated by one or more image edges.
2: Part or all of the cloud lies in the region of overlap
between two images.
3: Core mass is an upper limit due to significant heating
by embedded stars
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History: Prepared via OCR at CDS.
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(End) James Marcout, Patricia Bauer [CDS] 25-Mar-1997