Changes between Version 53 and Version 54 of u/EricasLibrary

Timestamp:

03/11/13 12:56:52 (12 years ago)

Author:

Erica Kaminski

Comment:

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u/EricasLibrary

@@ -189 +189 @@
   Skipping to figure 3, for which the Pext doubles in a crossing time (aka strong compression). I have a hard time understanding their description in the text, p 874, right column, 2nd paragraph. They say a small compression wave moves in (I see this in plot), but they go on to say that before the wave converges on the center to form the sink (and class 0 phase - last 2 panes in figure), the central density has hardly changed "for the inner regions were unaware of Pext increasing". First of all, in the plot the central density is clearing increasing in panes 1-3. Second of all, they would be unaware only for a supersonic compression wave -- for which they did not establish exists. They say again that around the sink, a free fall v field is set up, but in the outer regions a uniform sonic field is established (v~0.12 km/s). Again, I do not see a uniform v field in the outer regions.. I assume what they mean is uniform in r... not for a fixed r over time..  This plot does however, seem to show a change in the velocity field from the early "compression wave phase" to the later "classic phase", in the language of my paper. Although I think these plots overall do a poor job showing the evolution of the flow since they only sample 3 time states before sink formation, they don't capture the dynamics very well.
 
+  In Figure 4 for even stronger compression, the compression wave is now evident in the plots. I see in their velocity plots a turn-over similar to wee see for the different phases of evolution. The last plot they show before the sink forms, seems to be indicating a compression wave is about to "converge on the center". However, we also saw this type of evolution, but between this time and sink formation in our runs, the density profile evened out to a collapsing BE profile. I wonder if Hennebelle et al found similar results, and if so, why they did not choose to report it... This case seems most like our Matched case.
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+  In Figure 5, the compression wave seems to completely rip through the BE sphere, although no mention of the speed of the incoming compression wave is given (which would have been interesting to compare to the triggered star formation stuff Shule has been looking at, which for mach > 20 has been shown to disrupt the BE sphere from being able to form a sink). It seems like the compression wave keeps building mass because of the abrupt increasing change in Pext that adds density to the wave in an isothermal fashion. 
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+  The results section concludes with the authors saying that when Pext is increased but then kept steady the results are different, citing figure 6. They do not ellaborate, so the reader is left  to guess at what features they may be referring to. Looking at these plots, I am curious why the turn-up in vrad at large radii... We also saw a turn up in vrad in some cases... 
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