radiative transfer

Simulating Lyman-alpha Emitters

Below plots show first results of our new radiative transfer code for meshless structures applied to individual halos in the IllustrisTNG simulations. Lyman-alpha emitter after radiative transfer. Surface brightness in erg/s/cm$^2$/arcsec$^2$. Lyman-alpha emitter after radiative transfer. Artificially lowered neutral hydrogen density by a factor of $10$, revealing the radiative transfer smoothing out the emission from the star forming regions. Surface brightness in erg/s/cm$^2$/arcsec$^2$. The neutral hydrogen column density responsible for scattering out the injected photons in star forming regions.

IGM Interaction of Lyman-alpha Emitters Spectra

Lyman-alpha emitters (LAEs) show a rich variety of spectral shapes due to the emission line’s resonant nature and typically high optical depths. While there is a large body of literature exploring how small-scale density and velocity distributions can explain this variety of features in spectra, the intergalactic medium (IGM) has often been neglecting as a contributing factor for such features. Above sketch helps visualizing how the IGM density and velocity structure along a line-of-sight give rise to an attenuation profile possibly shaping the arising spectrum.

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. 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. Lately, we expanded the priorly used code in Behrens et al., 2019 ( public version here) to work on such meshless structure.