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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We use idealized N-body simulations of equilibrium stellar disks embeddedwithin course-grained dark matter haloes to study the effects of spuriouscollisional heating on disk structure and kinematics. Collisional heatingartificially increases the vertical and radial velocity dispersions of diskstars, as well as the thickness and size of disks; the effects are felt at allgalacto-centric radii. The integrated effects of collisional heating aredetermined by the mass of dark matter halo particles (or equivalently, by thenumber of particles at fixed halo mass), their local density and characteristicvelocity dispersion, but are largely insensitive to the stellar particle mass.The effects can therefore be reduced by increasing the mass resolution of darkmatter in cosmological simulations, with limited benefits from increasing thebaryonic (or stellar) mass resolution. We provide a simple empirical model thataccurately captures the effects of spurious collisional heating on thestructure and kinematics of simulated disks, and use it to assess theimportance of disk heating for simulations of galaxy formation. We find thatthe majority of state-of-the-art zoom simulations, and a few of thehighest-resolution, smallest-volume cosmological runs, are in principle able toresolve thin stellar disks in Milky Way-mass haloes, but most large-volumecosmological simulations cannot. For example, dark matter haloes resolved withfewer than $\approx 10^6$ particles will collisionally heat stars near thestellar half-mass radius such that their vertical velocity dispersion increasesby $\gtrsim 10$ per cent of the halo's virial velocity in approximately oneHubble time.

Spurious heating of stellar motions in simulated galactic disks by dark matter halo particles