2022A&A...666A.165S


Query : 2022A&A...666A.165S

2022A&A...666A.165S - Astronomy and Astrophysics, volume 666A, 165 (2022/10-1)

Understanding star formation in molecular clouds IV. Column density PDFs from quiescent to massive molecular clouds.

SCHNEIDER N., OSSENKOPF-OKADA V., CLARKE S., KLESSEN R.S., KABANOVIC S., VELTCHEV T., BONTEMPS S., DIB S., CSENGERI T., FEDERRATH C., DI FRANCESCO J., MOTTE F., ANDRE P., ARZOUMANIAN D., BEATTIE J.R., BONNE L., DIDELON P., ELIA D., KONYVES V., KRITSUK A., LADJELATE B., MYERS P., PEZZUTO S., ROBITAILLE J.F., ROY A., SEIFRIED D., SIMON R., SOLER J. and WARD-THOMPSON D.

Abstract (from CDS):

Probability distribution functions of the total hydrogen column density (N-PDFs) are a valuable tool for distinguishing between the various processes (turbulence, gravity, radiative feedback, magnetic fields) governing the morphological and dynamical structure of the interstellar medium. We present N-PDFs of 29 Galactic regions obtained from Herschel imaging at high angular resolution (18″), covering diffuse and quiescent clouds, and those showing low-, intermediate-, and high-mass star formation (SF), and characterize the cloud structure using the ∆-variance tool. The N-PDFs show a large variety of morphologies. They are all double-log-normal at low column densities, and display one or two power law tails (PLTs) at higher column densities. For diffuse, quiescent, and low-mass SF clouds, we propose that the two log-normals arise from the atomic and molecular phase, respectively. For massive clouds, we suggest that the first log-normal is built up by turbulently mixed H2 and the second one by compressed (via stellar feedback) molecular gas. Nearly all clouds have two PLTs with slopes consistent with self-gravity, where the second one can be flatter or steeper than the first one. A flatter PLT could be caused by stellar feedback or other physical processes that slow down collapse and reduce the flow of mass toward higher densities. The steeper slope could arise if the magnetic field is oriented perpendicular to the LOS column density distribution. The first deviation point (DP), where the N-PDF turns from log-normal into a PLT, shows a clustering around values of a visual extinction of AV (DP1) ∼ 2-5. The second DP, which defines the break between the two PLTs, varies strongly. In contrast, the width of the N-PDFs is the most stable parameter, with values of σ between ∼0.5 and 0.6. Using the ∆-variance tool, we observe that the AV value, where the slope changes between the first and second PLT, increases with the characteristic size scale in the ∆-variance spectrum. We conclude that at low column densities, atomic and molecular gas is turbulently mixed, while at high column densities, the gas is fully molecular and dominated by self-gravity. The best fitting model N-PDFs of molecular clouds is thus one with log-normal low column density distributions, followed by one or two PLTs.

Abstract Copyright: © N. Schneider et al. 2022

Journal keyword(s): methods: statistical - ISM: clouds - dust, extinction - ISM: general - evolution - ISM: structure

Simbad objects: 39

goto Full paper

goto View the references in ADS

Number of rows : 39
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 W 3 MoC 02 27 04.10 +61 52 27.1           ~ 1033 3
2 * alf UMi cC* 02 31 49.09456 +89 15 50.7923 3.00 2.62 2.02 1.53 1.22 F8Ib 673 2
3 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1371 0
4 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4429 0
5 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1379 0
6 NAME Mon R2 HII 06 07 47.58 -06 22 42.6           ~ 744 2
7 NAME Rosette Nebula HII 06 32 26.76 +04 47 37.1           ~ 492 1
8 NAME Mon I MoC 06 35 +10.1           ~ 256 0
9 NGC 2264 OpC 06 40 52.1 +09 52 37           ~ 1793 0
10 NAME Vela C Cld 08 57 -43.2           ~ 179 0
11 RCW 36 HII 08 59 00.9 -43 44 10     15.20     ~ 147 0
12 NAME Musca Filament PoC 10 54 -74.0           ~ 40 0
13 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1154 1
14 NAME Musca Cld 12 23 -71.3           ~ 222 0
15 NAME Cha III MoC 12 37.8 -80 15           ~ 140 2
16 NAME Cha II MoC 12 54 -77.2           ~ 337 0
17 Lupus 1 Cld 15 43 02.1 -34 09 06           ~ 286 0
18 NAME Lupus Complex SFR 16 03 -38.1           ~ 720 0
19 Lupus 4 MoC 16 03 12.4 -42 07 43           ~ 152 0
20 Lupus 3 SFR 16 09.6 -39 03           ~ 323 0
21 Lupus 6 Cld 16 25 -40.3           ~ 51 1
22 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3636 1
23 NAME Draco Nebula RNe 16 52 +61.0           ~ 55 0
24 SH 2-3 HII 17 12.4 -38 28           ~ 206 1
25 NGC 6334 HII 17 20 53 -36 07.9           ~ 683 0
26 NGC 6357 OpC 17 24 44 -34 12.2           ~ 274 0
27 NAME the Pipe Nebula DNe 17 30 -25.0           ~ 403 1
28 W 33a Y*O 18 14 39.56547 -17 52 02.2260           ~ 698 0
29 M 16 OpC 18 18 45.1 -13 47 31           ~ 1029 1
30 NGC 6618 OpC 18 20 47 -16 10.3           ~ 1615 0
31 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 1103 2
32 NAME Aql Region reg 18 31.1 -02 10           ~ 392 0
33 NAME Northern Coalsack DNe 20 21 +37.0           ~ 117 0
34 NAME Cyg X BL? 20 30 04.7973633 +40 51 36.002197           ~ 848 1
35 NAME Cygnus X South MoC 20 34.0 +39 35           ~ 14 0
36 NAME Cygnus X North MoC 20 37.0 +41 56           ~ 25 0
37 IC 5146 OpC 21 53 29.3 +47 14 46           ~ 468 2
38 NGC 7538 OpC 23 13 37 +61 30.0           ~ 881 1
39 NAME Gould Belt PoG ~ ~           ~ 874 1

To bookmark this query, right click on this link: simbad:objects in 2022A&A...666A.165S and select 'bookmark this link' or equivalent in the popup menu