Dark matter resolution?

SciTech Daily has an article on ALMA's work trying to locate dark matter. The Figure 1 doesn't seem to appear in the paper itself. The figure looks very odd. The caption says it depicts calculated fluctions in dark matter density--it looks grid-like. I assume there's more elsewhere. The figures in the paper don't look quite so regular. Regularity like that of Figure 1 makes me suspicious--is it an artifact of their procedure?

Unfortunately I'm not familiar with the tools described in the paper, so I can't guess.

If their work pans out, they're getting much better resolution than before thanks to a more sophisticated analysis. I'll bet a number of the MOND people are already all over it, so we should find out soon.