EDP Sciences
Highlight
Free Access
Issue
A&A
Volume 556, August 2013
Article Number A153
Number of page(s) 18
Section Astrophysical processes
DOI https://doi.org/10.1051/0004-6361/201321292
Published online 09 August 2013

Online material

Appendix A: Results of decaying turbulence with a magnetic field tilted with respect to the mesh

Because we found in this paper that the clumps are more filamentary in magnetized flows, it is important to verify that no obvious numerical artifact is producing this effect. We therefore repeated one of the runs (decaying turbulence with 5 μG and one level of AMR) with a magnetic field initially tilted to 45° with respect to the mesh. Figures A.1 and A.2 show the bidimensional distribution μ1/μ2 vs. μ2/μ3 and the histogram of cos(α), the cosine of the angle between the filament axis and the strain, respectivelly. As can be seen, they are very similar to the corresponding results shown for the untilted case.

thumbnail Fig. A.1

Normalized bidimensional histogram displaying μ1/μ2 as a function of μ2/μ3 for the decaying turbulence simulation with inclined magnetic field at time 1.32 Myr.

Open with DEXTER

thumbnail Fig. A.2

Distribution of cosα (the angle between the main axis and the strain) in the clumps for the decaying turbulence simulation with inclined magnetic field at time 1.32 Myr.

Open with DEXTER

Appendix B: Results of colliding flow simulations

Here we present the results obtained for the colliding-flow simulations. These simulations are described in Sect. 2.3.2. The purpose of this appendix is to demonstrate that the results obtained in the paper are not a consequence of a particular choice of initial and boundary conditions. We used time steps that represent a similar evolution. For the four runs, significant masses of gas (typically 104  M of gas denser than 100 cm-3) were accumulated, and at several places, collapse has proceeded or is still proceeding. We restrict our attention to the most important quantities that were studied namely the clump aspect ratio computed using the inertia matrix and the skeleton-like approach, the length and thickness of the clumps, the cosine of the angle between the clump axis, and the strain and the divergence over strain ratio. In the six plots the solid line represents the high-resolution intermediate magnetization run, the dotted line is the standard resolution intermediate magnetization one, the dashed line represents the highly magnetized run while the dot-dashed line displays the hydrodynamical simulation.

thumbnail Fig. B.1

Distribution of aspect ratio, μ3/μ1 of the clumps (threshold 500 cm-3). Solid line: high-resolution intermediate magnetization run at time 12.94 Myr. Dotted line: standard resolution intermediate magnetization run at time 16.82 Myr. Dashed line: highly magnetized run at time 18 Myr. Dot-dashed line: hydrodynamical run at time 15.1 Myr.

Open with DEXTER

thumbnail Fig. B.2

Same as Fig. B.1 for the distribution of aspect ratio, R/L of the clumps (threshold 500 cm-3).

Open with DEXTER

thumbnail Fig. B.3

Same as Fig. B.1 for the length distribution of the clumps.

Open with DEXTER

Figures B.1 and B.2 show very similar trends with Figs. 6, 7, 9 and 10. In particular, in the hydrodynamical simulation the clumps have larger aspect ratios than in the MHD simulations.

The length and the thickness of the clumps are very similar to what has been inferred in the decaying simulations. The peaks are also located at the same position of about 0.5 pc for the length and 0.1 pc for the thickness.

In Fig. B.5 the trends of the filament axis and the strain to be preferentially aligned is also clear. As for the decaying turbulence simulations, it is more pronounced for the magnetized than for the hydrodynamical runs.

Figure B.6 is also very similar to the trends inferred in Figs. 17 and 18 that were discussed previously.

thumbnail Fig. B.4

Same as Fig. B.1 for the thickness distribution of the clumps.

Open with DEXTER

thumbnail Fig. B.5

Same as Fig. B.1 for the distribution of cosα (the angle between the main axis and the strain) in the clumps.

Open with DEXTER

thumbnail Fig. B.6

Same as Fig. B.1 for the ratio distribution of the divergence and strain in the clumps.

Open with DEXTER


© ESO, 2013

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.