English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We compute the generation of vorticity from velocity dispersion in the darkmatter fluid. For dark matter at zero temperature Helmholtz's theorem dictatesthat no vorticity is generated and we therefore allow the dark matter fluid tohave a non-vanishing velocity dispersion. This implies a modification to theusual hydrodynamical system (continuity and Euler equations): we have toconsider the Boltzmann hierarchy up to the second moment. This means that theEuler equation is modified with a source term that describes the effect ofnon-zero velocity dispersion. We write an equation for the Eulerian vorticityin Lagrangian coordinates and show that it has a growing mode already at secondorder in perturbation theory. We compute the power spectrum of the vorticityand the rotational velocity at second order in perturbation theory.

Vorticity generation in the Universe: A perturbative approach