Query : 2013A&A...557A.120K

2013A&A...557A.120K - Astronomy and Astrophysics, volume 557A, 120-120 (2013/9-1)

High-fidelity view of the structure and fragmentation of the high-mass, filamentary IRDC G11.11-0.12.


Abstract (from CDS):

Star formation in molecular clouds is intimately linked to their internal mass distribution. We present an unprecedentedly detailed analysis of the column density structure of a high-mass, filamentary molecular cloud, namely IRDC G11.11-0.12 (G11). We use two novel column density mapping techniques: high-resolution (FWHM=2", or ∼0.035pc) dust extinction mapping in near- and mid-infrared, and dust emission mapping with the Herschel satellite. These two completely independent techniques yield a strikingly good agreement, highlighting their complementarity and robustness. We first analyze the dense gas mass fraction and linear mass density of G11. We show that G11 has a top heavy mass distribution and has a linear mass density (Ml∼600M/pc) that greatly exceeds the critical value of a self-gravitating, non-turbulent cylinder. These properties make G11 analogous to the Orion A cloud, despite its low star-forming activity. This suggests that the amount of dense gas in molecular clouds is more closely connected to environmental parameters or global processes than to the star-forming efficiency of the cloud. We then examine hierarchical fragmentation in G11 over a wide range of size-scales and densities. We show that at scales 0.5pc>l>8pc, the fragmentation of G11 is in agreement with that of a self-gravitating cylinder. At scales smaller than l≲0.5pc, the results agree better with spherical Jeans' fragmentation. One possible explanation for the change in fragmentation characteristics is the size-scale-dependent collapse time-scale that results from the finite size of real molecular clouds: at scales l≲0.5pc, fragmentation becomes sufficiently rapid to be unaffected by global instabilities.

Abstract Copyright:

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

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 Barnard 213 DNe 04 20 51 +27 16.3           ~ 206 0
2 NAME Ori A MoC 05 38 -07.1           ~ 2952 0
3 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 4247 4
4 [CCE98b] 011.11-0.12 Cld 18 10.5 -19 23           ~ 96 2

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