Radiative Transfer on Voronoi Meshes

Radiative Transfer on Voronoi Meshes

An increasing amount of astrophysical and cosmological simulations are carried out on a moving unstructed mesh defined by the Voronoi tessellation.

Lately, we expanded the priorly used code in Behrens et al., 2019 (public version here) to work on such meshless structure. This will ensure the code’s relevance in the future and application to new simulations that would not have been able to be processed with prior code due to the larger memory requirement due to an intermediate interpolation step. First applications of the new code include IGM transmission and simulating individual LAEs.

Photons are spawned in a Monte Carlo fashion from emitting gas cells. At each scattering the contribution reaching the observer along specified lines of sight is computed.

Zoom of edge-on view onto galaxy in IllustrisTNG100 at z=3. On shown scales, the Voronoi gas cells have a maximal resolution of 0.3 kpc. Outside of star-forming regions the resolution can be in the order of kpcs. Those Voronoi cells become visible on zoom-ins in the radiative transfer simulations. Yellow regions are well traced out by photons, indicating high HI densities, whereas the cell shapes are not traced in blue regions due to lower densities.

Chris Byrohl
Second year PhD Candidate in Physical Cosmology