2013A&A...549A..53K


Query : 2013A&A...549A..53K

2013A&A...549A..53K - Astronomy and Astrophysics, volume 549A, 53-53 (2013/1-1)

High-dynamic-range extinction mapping of infrared dark clouds. Dependence of density variance with sonic mach number in molecular clouds.

KAINULAINEN J. and TAN J.C.

Abstract (from CDS):

Measuring the mass distribution of infrared dark clouds (IRDCs) over the wide dynamic range of their column densities is a fundamental obstacle in determining the initial conditions of high-mass star formation and star cluster formation. We present a new technique to derive high-dynamic-range, arcsecond-scale resolution column density data for IRDCs and demonstrate the potential of such data in measuring the density variance - sonic Mach number relation in molecular clouds. We combine near-infrared data from the UKIDSS/Galactic Plane Survey with mid-infrared data from the Spitzer/GLIMPSE survey to derive dust extinction maps for a sample of ten IRDCs. We then examine the linewidths of the IRDCs using 13CO line emission data from the FCRAO/Galactic Ring Survey and derive a column density - sonic Mach number relation for them. For comparison, we also examine the relation in a sample of nearby molecular clouds. The presented column density mapping technique provides a very capable, temperature independent tool for mapping IRDCs over the column density range equivalent to AV≃1-100mag at a resolution of 2''. Using the data provided by the technique, we present the first direct measurement of the relationship between the column density dispersion, σN/<N>, and sonic Mach number, Ms, in molecular clouds. We detect correlation between the variables with about 3-σ confidence. We derive the relation σN/<N>≃(0.047±0.016)Ms, which is suggestive of the correlation coefficient between the volume density and sonic Mach number, σρ/<ρ>≃(0.20+0.37–0.22)Ms, in which the quoted uncertainties indicate the 3-σ range. When coupled with the results of recent numerical works, the existence of the correlation supports the picture of weak correlation between the magnetic field strength and density in molecular clouds (i.e., B ∝ρ0.5). While our results remain suggestive because of the small number of clouds in our demonstration sample, the analysis can be improved by extending the study to a larger number of clouds.

Abstract Copyright:

Journal keyword(s): ISM: clouds - dust, extinction - ISM: structure - stars: formation - infrared: ISM

Simbad objects: 29

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Number of rows : 29
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 LDN 1333 DNe 02 26 04 +75 28.5           ~ 55 0
2 NAME Chandra Deep Field-South reg 03 32 28.0 -27 48 30           ~ 2003 1
3 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1266 0
4 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4096 0
5 NAME Ori A MoC 05 38 -07.1           ~ 2897 0
6 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1303 0
7 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1095 1
8 IRAS 12340-7958 LP* 12 37 39.7408011816 -80 15 13.707391932   16.11 14.39 13.63 9.81 ~ 106 0
9 NAME Cha III MoC 12 37.8 -80 15           ~ 136 2
10 NAME Cha II MoC 12 54 -77.2           ~ 321 0
11 LDN 134 MoC 15 53 36.3 -04 35 26           ~ 202 0
12 LDN 1719 DNe 16 19.9 -20 07           ~ 23 0
13 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3446 1
14 LDN 204 DNe 16 47 47.3 -12 05 16           ~ 54 0
15 MSXDC G019.27+0.07 DNe 18 25 54.0 -12 04 56           ~ 11 0
16 MSXDC G018.82-0.28 DNe 18 26 19.8 -12 41 30           ~ 11 0
17 NAME Dragon Nebula DNe 18 42 50.6 -04 03 30           ~ 138 0
18 MSXDC G028.67+0.13 DNe 18 43 07.9 -03 44 29           ~ 12 0
19 MSXDC G028.53-0.25 DNe 18 44 17.1 -03 59 37           ~ 20 0
20 MSXDC G034.43+0.24 MoC 18 53 18.9 +01 26 39           ~ 88 0
21 MSXDC G034.77-0.55 DNe 18 56 48.8 +01 23 21           ~ 17 0
22 MSXDC G035.39-0.33 MoC 18 57 09.0 +02 07 46           ~ 108 0
23 NAME Corona Australis Cloud MoC 19 01 51 -36 58.9           ~ 455 0
24 MSXDC G038.95-0.47 DNe 19 04 08.3 +05 08 49           ~ 15 0
25 MSXDC G053.11+0.05 DNe 19 29 18.1 +17 54 33           ~ 13 0
26 IRAS 20582+7724 Y*O 20 57 12.9250225656 +77 35 43.656301932           ~ 116 0
27 LDN 1228 DNe 20 57 13 +77 35.8           ~ 127 0
28 IC 5146 OpC 21 53 29 +47 14.8           ~ 444 2
29 NAME Cepheus A SFR 22 56 17.9 +62 01 49           ~ 725 2

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2023.02.02-18:55:24

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