Cosmic ray feedback and constraints on cosmic ray propagation

We have successfully implemented cosmic rays (CRs) in GIZMO. We model cosmic rays with a two fluid models (gas+CRs) with diffusion and streaming.

I have given a talk in the 2018 Santa Cruz galaxy workshop:

The slide is available here: TsangKeungChan_CRdrivenwind

I have also worked on simulating pionic gamma ray emission from cosmic rays, which can be seen in the poster ( Poster_CR_A0) I presented in the 15th Potsdam Thinkshop.

 

Here are some cool movies featuring cosmic ray feedback on different galaxies!

Images are weighted by mass times temperature, so higher temperature gas (>10^3K) is more visible.

The movie below shows idealized dwarf galaxies with (left) and without cosmic rays (right) (with isotropic diffusion coefficient 3e28cm^2/s). Surprisingly, cosmic rays allow more cold gas (magenta) to stay within the disks.

MW-mass galaxies with (left) and without cosmic rays (right). There is significant fast outflowing hot gas on the left but warm slow outflowing gas on the right at late times:

Starburst galaxies with (right) and without (left) cosmic ray (diffusion coefficient=3e28cm^2/s):