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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Small-scale structure is studied in the context of dissipative dark matter,arising for instance in models with a hidden unbroken Abelian sector, so thatdark matter couples to a massless dark photon. The dark sector interacts withordinary matter via gravity and photon-dark photon kinetic mixing. Mirror darkmatter is a theoretically constrained special case where all parameters arefixed except for the kinetic mixing strength, $\epsilon$. In these models, thedark matter halo around spiral and irregular galaxies takes the form of adissipative plasma which evolves in response to various heating and coolingprocesses. It has been argued previously that such dynamics can account for theinferred cored density profiles of galaxies and other related structuralfeatures. Here we focus on the apparent deficit of nearby small galaxies("missing satellite problem"), which these dissipative models have thepotential to address through small-scale power suppression by acoustic anddiffusion damping. Using a variant of the extended Press-Schechter formalism,we evaluate the halo mass function for the special case of mirror dark matter.Considering a simplified model where $M_{\text{baryons}} \proptoM_{\text{halo}}$, we relate the halo mass function to more directly observablequantities, and find that for $\epsilon/10^{-10} \approx 2$ such a simplifieddescription is compatible with the measured galaxy luminosity and velocityfunctions. On scales $M_{\text{halo}} \lesssim 10^8 \ M_\odot$, diffusiondamping exponentially suppresses the halo mass function, suggesting anonprimordial origin for dwarf spheroidal satellite galaxies, which wespeculate were formed via a top-down fragmentation process as the result ofnonlinear dissipative collapse of larger density perturbation. This couldexplain the planar orientation of satellite galaxies around Andromeda and theMilky Way.

Solving the small-scale structure puzzles with dissipative dark matter