J/ApJ/698/324 Spitzer IRDCs (Ragan+, 2009)
Detection of structure in infrared-dark clouds with Spitzer:
characterizing star formation in the molecular ring.
Ragan S.E., Bergin E.A., Gutermuth R.A.
<Astrophys. J., 698, 324-349 (2009)>
=2009ApJ...698..324R 2009ApJ...698..324R
ADC_Keywords: Molecular clouds ; Photometry, infrared ; YSOs ;
Interstellar medium
Keywords: ISM: clouds - stars: formation
Abstract:
We have conducted a survey of a sample of infrared-dark clouds (IRDCs)
with the Spitzer Space Telescope in order to explore their mass
distribution. We present a method for tracing mass using dust
absorption against the bright Galactic background at 8um. The IRDCs in
this sample are comprised of tens of clumps, ranging in sizes from
0.02 to 0.3pc in diameter and masses from 0.5 to a few 103M☉,
the broadest dynamic range in any clump mass spectrum study to date.
Description:
In order to study substructure with Spitzer, we have selected a sample
of targets from the Ragan et al. (2006, Cat. J/ApJS/166/567) sample
which are compact, typically 2'x2' (or 2x2pc at 4kpc), and opaque,
providing the starkest contrast at 8um (Midcourse Science Experiment
(MSX) Band A) with which to examine the absorbing structure. The 11
IRDCs observed are listed in Table 1.
Observations of this sample of objects were made on 2005 May 7-9 and
September 15-18 with Infrared Array Camera (IRAC) centered on the
coordinates listed in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 46 11 Spitzer targets
table2.dat 136 309 Spitzer-identified YSOs: 2MASS, IRAC, and MIPS
photometry
table6.dat 66 451 Clumpfind results, foreground estimation
method A
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/A+A/505/405 : A catalogue of Spitzer dark clouds (Peretto+, 2009)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJ/663/1149 : Spitzer survey of Serpens YSO population (Harvey+, 2007)
J/ApJS/166/567 : Radio Molecular lines in infrared dark clouds (Ragan+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- IRDC IRDC identification (GLLL.ll+B.bb)
14- 15 I2 h RAh Hour of right ascension (J2000)
17- 18 I2 min RAm Minute of right ascension (J2000)
20- 21 I2 s RAs Second of right ascension (J2000)
23 A1 --- DE- Sign of declination (J2000)
24- 25 I2 deg DEd Degree of declination (J2000)
27- 28 I2 arcmin DEm Arcminute of declination (J2000)
30- 31 I2 arcsec DEs Arcsecond of declination (J2000)
33- 36 F4.2 kpc Dist Distance (1)
38- 41 F4.2 kpc E_Dist Positive error on Dist (1)
43- 46 F4.2 kpc e_Dist Negative error on Dist (1)
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Note (1): Distances derived from Ragan et al. (2006, Cat. J/ApJS/166/567)
using a Milky Way rotation curve model (Fich et al. 1989ApJ...342..272F 1989ApJ...342..272F)
assuming the "near" kinematic distance. The listed uncertainties arise
from the ±14% maximal deviation inherent in the rotation curve model.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- IRDC IRDC identification (GLLL.ll+B.bb)
14- 15 I2 --- Seq [1/46] Index number
17- 18 I2 h RAh Hour of Right Ascension (J2000)
20- 21 I2 min RAm Minute of Right Ascension (J2000)
23- 27 F5.2 s RAs Second of Right Ascension (J2000)
29 A1 --- DE- Sign of the Declination (J2000)
30- 31 I2 deg DEd Degree of Declination (J2000)
33- 34 I2 arcmin DEm Arcminute of Declination (J2000)
36- 39 F4.1 arcsec DEs Arcsecond of Declination (J2000)
41- 45 F5.2 mag Jmag ? 2MASS J band magnitude
47- 50 F4.2 mag e_Jmag ? Uncertainty in Jmag
52- 56 F5.2 mag Hmag ? 2MASS H band magnitude
58- 61 F4.2 mag e_Hmag ? Uncertainty in Hmag
63- 67 F5.2 mag Ksmag ? 2MASS Ks band magnitude
69- 72 F4.2 mag e_Ksmag ? Uncertainty in Ksmag
74- 78 F5.2 mag [3.6] ? Spitzer/IRAC 3.6 micron band magnitude
80- 83 F4.2 mag e_[3.6] ? Uncertainty in [3.6]
85- 89 F5.2 mag [4.5] Spitzer/IRAC 4.5 micron band magnitude
91- 94 F4.2 mag e_[4.5] Uncertainty in [4.5]
96-100 F5.2 mag [5.8] ? Spitzer/IRAC 5.8 micron band magnitude
102-105 F4.2 mag e_[5.8] ? Uncertainty in [5.8]
107-111 F5.2 mag [8.0] ? Spitzer/IRAC 8.0 micron band magnitude
113-116 F4.2 mag e_[8.0] ? Uncertainty in [8.0]
118-121 F4.2 mag [24] ? Spitzer/MIPS 24.0 micron band magnitude
123-126 F4.2 mag e_[24] ? Uncertainty in [24]
128-132 F5.3 mag AK ? The Ks band extinction
134-136 A3 --- Class Classification of the YSO (1)
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Note (1): Classification as follows:
CI = class I protostar;
CII = class II pre-main sequence star;
TD = transition disk;
EP = embedded protostar.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- IRDC IRDC identification (GLLL.ll+B.bb)
14- 16 A3 --- CSeq Clump number (CNN)
18- 21 I4 arcsec offRA Offset in Right Ascension from center
23- 26 I4 arcsec offDE Offset in Declination from center
28- 33 F6.1 Msun CMass Clump mass
35- 38 F4.2 --- tau Maximum optical depth
40- 43 F4.2 pc CSize Clump size
45- 66 A22 --- Notes Additional notes (1)
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Note (1): Numbers indicate which stars from Table 2 are associated with a
given clump. The YSO type (CI = Class I; CII = Class II; EP = Embedded
Protostar; TD = Transition Disk) is also listed. The "fg" denotation
indicates that a foreground (or background) star in the field may
contaminate the properties listed for that clump.
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Nomenclature Notes:
Table 1: <[RBP2006] GLL.ll+B.bb> in Simbad,
Table 2: <[RBG2009] GLLL.ll+B.bb NN> in Simbad,
Table 6: <[RBG2009] GLLL.ll+B.bb CNN> in Simbad.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 03-Jun-2011