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/

Zendy Plus

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

Zendy Tools

Zendy Open

The physics of cosmic rays (CR) is a promising candidate for explaining thedriving of galactic winds and outflows. Recent galaxy formation simulationshave demonstrated the need for active CR transport either in the form ofdiffusion or streaming to successfully launch winds in galaxies. However, dueto computational limitations, most previous simulations have modeled CRtransport isotropically. Here, we discuss high resolution simulations ofisolated disk galaxies in a $10^{11}\rm{M_\odot}$ halo with the moving meshcode {\sc Arepo} that include injection of CRs from supernovae, advectivetransport, CR cooling, and CR transport through isotropic or anisotropicdiffusion. We show that either mode of diffusion leads to the formation ofstrong bipolar outflows. However, they develop significantly later in thesimulation with anisotropic diffusion compared to the simulation with isotropicdiffusion. Moreover, we find that isotropic diffusion allows most of the CRs toquickly diffuse out of the disk, while in the simulation with anisotropicdiffusion, most CRs remain in the disk once the magnetic field becomesdominated by its azimuthal component, which occurs after $\sim 300\,{\rmMyrs}$. This has important consequences for the gas dynamics in the disk. Inparticular, we show that isotropic diffusion strongly suppresses theamplification of the magnetic field in the disk compared to anisotropic or nodiffusion models. We therefore conclude that reliable simulations which includeCR transport inevitably need to account for anisotropic diffusion.

Galactic winds driven by isotropic and anisotropic cosmic ray diffusion in disk galaxies