2011A&A...530A..64K


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.10CEST02:22:07

2011A&A...530A..64K - Astronomy and Astrophysics, volume 530A, 64-64 (2011/6-1)

Probing the evolution of molecular cloud structure. II. From chaos to confinement.

KAINULAINEN J., BEUTHER H., BANERJEE R., FEDERRATH C. and HENNING T.

Abstract (from CDS):

We present an analysis of the large-scale molecular cloud structure and of the stability of clumpy structures in nearby molecular clouds. In our recent work, we identified a structural transition in molecular clouds by studying the probability distributions of their gas column densities. In this paper, we further examine the nature of this transition. The transition takes place at the visual extinction of AVtail=2-4mag, or equivalently, at Σtail≃40-80M/pc2. The clumps identified above this limit have wide ranges of masses and sizes, but a remarkably constant mean volume density of <n≥∼103cm–3. This is 5-10 times higher than the density of the medium surrounding the clumps. By examining the stability of the clumps, we show that they are gravitationally unbound entities, and that the external pressure from the parental molecular cloud is a significant source of confining pressure for them. Then, the structural transition at AVtail may be linked to a transition between this population and the surrounding medium. The star-formation rates in the clouds correlate strongly with the total mass in the clumps, i.e., with the mass above AVtail, and drops abruptly below that threshold. These results imply that the formation of pressure-confined clumps introduces a prerequisite for star formation. Furthermore, they give a physically motivated explanation for the recently reported relation between the star-formation rates and the amount of dense material in molecular clouds. Likewise, they give rise to a natural threshold for star formation at AVtail.

Abstract Copyright:

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

Simbad objects: 26

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Number of rows : 26

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 LDN 1333 DNe 02 26 04 +75 28.5           ~ 52 0
2 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1071 0
3 NAME California Molecular Cloud MoC 04 10.0 +39 00           ~ 96 1
4 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3502 0
5 NAME Ori A MoC 05 38 -07.1           ~ 2680 0
6 NAME Cha I MoC 11 06 48 -77 18.0           ~ 973 1
7 NAME Musca Cld 12 23 -71.3           ~ 157 0
8 NAME Coalsack Nebula DNe 12 31 19 -63 44.6           ~ 242 0
9 IRAS 12340-7958 * 12 37 39.7466355997 -80 15 13.713429632   16.11 14.39 13.63 9.81 ~ 101 0
10 NAME Cha III MoC 12 37.8 -80 15           ~ 124 2
11 NAME Cha II MoC 12 54 -77.2           ~ 296 0
12 NAME Lupus I Cld 15 43 02.1 -34 09 06           ~ 225 0
13 LDN 134 MoC 15 53 36.3 -04 35 26           ~ 194 0
14 NAME Lupus III SFR 16 09.6 -39 03           ~ 271 0
15 LDN 1719 DNe 16 19.9 -20 07           ~ 21 0
16 NAME Lupus V MoC 16 21 -37.5           ~ 53 0
17 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3037 0
18 LDN 204 DNe 16 47 47.3 -12 05 16           ~ 51 0
19 NAME Oph Cluster ClG 17 12 24.7 -23 21 01           ~ 241 0
20 NAME the Pipe Nebula DNe 17 30 -25.0           ~ 336 1
21 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 918 2
22 NAME CrA Dark Cloud MoC 19 01 51 -36 58.9           ~ 397 0
23 IRAS 20582+7724 Y*O 20 57 12.9187221407 +77 35 43.655738044           ~ 113 0
24 LDN 1228 DNe 20 57 13 +77 35.8           ~ 121 0
25 NAME Cepheus A SFR 22 56 17.9 +62 01 49           ~ 698 2
26 NAME Ori B GMC MoC ~ ~           ~ 14 0

    Equat.    Gal    SGal    Ecl

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2020.08.10-02:22:07

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