J/A+A/561/A148 Mass Distribution of Infrared Dark Clouds (Gomez+, 2014)
The mass distribution of clumps within infrared dark clouds. A Large APEX
Bolometer Camera study.
Gomez L., Wyrowski F., Shculler F., Menten K.M., Ballesteros-Paredes J.
<Astron. Astrophys. 561, A148 (2014)>
=2014A&A...561A.148G 2014A&A...561A.148G
ADC_Keywords: Infrared sources ; Molecular clouds ; Millimetric/submm sources
Keywords: stars: formation - ISM: clouds - dust, extinction - submillimeter: ISM
Abstract:
We present an analysis of the dust continuum emission at 870um in
order to investigate the mass distribution of clumps within infrared
dark clouds (IRDCs). We map six IRDCs with the Large APEX BOlometer
CAmera (LABOCA) at APEX, reaching an rms noise level of 28-44mJy/beam.
The dust continuum emission coming from these IRDCs was decomposed by
using two automated algorithms, Gaussclumps and Clumpfind. We identify
510 and 352 sources with Gaussclumps and Clumpfind, respectively, and
estimate masses and other physical properties assuming a uniform dust
temperature. The mass ranges are 6-2692M☉(Gaussclumps) and
7-4254M_☉ (Clumpfind) and the ranges in effective radius are
around 0.10-0.74pc (Gaussclumps) and 0.16-0.99pc (Clumpfind). The mass
distribution, independent of the decomposition method used, is fitted
by a power law, dN/dM∝Malpha, with an index (alpha) of
-1.60±0.06.
Description:
Six southern hemisphere clouds with high extinction were observed on
2007-08-25/28 with the LABOCA (Large APEX BOlometer CAmera) instrument
on the APEX 12m telescope, at a frequency of 345GHz and a bandwidth of
610GHz (for the instrument, see Siringo et al. 2009A&A...497..945S 2009A&A...497..945S).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 98 510 Sources found with Gaussclumps algorithm
table4.dat 69 352 Sources found with Clumpfind algorithm
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See also:
J/ApJ/641/389 : Millimetric observations of IRDC cores (Rathborne+, 2006)
J/ApJ/680/349 : Galactic distribution of IRDCs (Jackson+, 2008)
J/ApJ/686/384 : 12CO, 13CO, C18O survey of IRDCs (Du+, 2008)
J/ApJ/698/324 : Spitzer IRDCs (Ragan+, 2009)
J/MNRAS/399/1506 : IRDC cores in SCUBA Legacy Catalogue (Parsons+, 2009)
J/ApJ/715/310 : Early stages of star formation in IRDCs (Rathborne+, 2010)
J/MNRAS/422/1071 : Cores in IR Dark Clouds for 300≤l≤330 (Wilcock+, 2012)
J/A+A/552/A40 : MSX high-contrast IRDCs with NH3 (Chira+, 2013)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Region Region (infra-red dark cloud) name (G1)
6- 8 I3 --- N [1/123] Running number within the region
10- 11 I2 h RAh Right ascension (J2000.0)
13- 14 I2 min RAm Right ascension (J2000.0)
16- 19 F4.1 s RAs Right ascension (J2000.0)
21 A1 --- DE- Declination sign (J2000.0)
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 29 I2 arcsec DEs Declination (J2000.0)
31- 36 F6.3 Jy Ipeak Peak intensity at 870um (345GHz) (in Jy/beam)
38- 43 F6.3 Jy S Flux density at 870um (345GHz)
45- 49 F5.1 arcsec amaj Angular FWHM along the major axis
51- 54 F4.1 arcsec amin Angular FWHM along the minor axis
56- 59 F4.2 pc dmaj Deconvolved FWHM along the major axis
61- 64 F4.2 pc dmin Deconvolved FWHM along the minor axis
66- 69 I4 deg PA [-180/180] Position angle
71- 74 F4.2 pc Reff Deconvolved effective radius
76- 79 I4 Msun Mass Total mass
81- 89 E9.3 cm-2 NH2 Beam averaged H2 column density
91- 98 E8.3 cm-3 nH2 H2 volume density
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Region Region (infra-red dark cloud) name (G1)
6- 8 I3 --- N [1/84] Running number within the region
10- 11 I2 h RAh Right ascension (J2000.0)
13- 14 I2 min RAm Right ascension (J2000.0)
16- 19 F4.1 s RAs Right ascension (J2000.0)
21 A1 --- DE- Declination sign (J2000.0)
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 29 I2 arcsec DEs Declination (J2000.0)
31- 36 F6.3 Jy Ipeak Peak intensity at 870um (345GHz) (in Jy/beam)
38- 43 F6.3 Jy S Flux density at 870um (345GHz)
45- 48 F4.2 pc Reff Deconvolved effective radius
50- 53 I4 Msun Mass Total mass
55- 62 E8.3 cm-2 NH2 Beam averaged H2 column density
64- 69 E6.3 cm-3 nH2 H2 volume density
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Note (G1):
The IRDC observed are G329=G329.03-0.2, G331=G331.38+0.2, G335=G335.25-0.3,
G337=G337.16-0.4. G343=G343.48-0.4. and G345=G345.07-0.2
Acknowledgements:
Laura Gomez, lgomez(at)das.uchile.cl
(End) Laura Gomez [Universidad de Chile], Patricia Vannier [CDS] 03-Jan-2014