On the Kinematic Morphology around Halos by Xiaolin Luo et al. on Monday 28 November

In this paper, we report an interesting kinematic phenomenon around the

halos' edge related to the splashback radius. After the shell-crossing, cosmic

flow exhibits various rotational morphologies via stream-mixing. Vorticity is

generated in a particular way that coincides with the large-scale structure.

Notably, one specific flow morphology, which is spiraling inward and

compressing in the third direction, concentrates around halos. A detailed

examination that reveals a sharp change in the logarithmic derivative of its

volume fraction, coincides with the location of the splashback radius defined

as the outermost caustic structure. Such a feature encodes valuable phase space

information and provides a new perspective on understanding the dynamical

evolution of halos. As a volume-weighted quantity, the profile of flow

morphology is purely kinematic. And unlike other related studies, the

rotational flow morphologies capture the anisotropic phase structure in the

multi-stream region.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.06488v3