Abstract

Contributed Talk - Splinter Computational

Thursday, 12 September 2024, 14:15   (S26)

Three-dimensional modelling of interstellar PDRs through clumpy ensembles

Aditi Sinha, Volker Ossenkopf-Okada, Sebastian Vider
University of Cologne

Modelling of photon-dominated regions (PDRs) is essential for understanding observations of massive star-forming regions as they tell us about the local chemistry and physics. Based on the KOSMA-τ model, Kosmatau3d uniquely simulates the inhomogeneous Interstellar medium (ISM) by taking the fractal approach where the PDR is approximated by an ensemble of self-similar clumps. To quantitatively interpret observations, kosmatau3d solves the radiative transfer equation through cubic voxels populated by clump ensembles to simulate the line and continuum emission (Yanitski 2023). We have incorporated our model into the SILCC (Simulating the Life-Cycle of molecular Clouds) simulations (Walch et. al. 2015) as a subgrid model in post-processing. At the boundaries of the simulations of HII regions, we first initialize the kosmatau3d voxel at the most probable PDR by calculating inputs like FUV, ensemble density, ensemble mass and velocity dispersion from the simulation grid itself. Using the simplest setup of a single voxel, we check how introducing clumpiness changes the simulated emission in this region by comparing the computed species with the abundances from SILCC. By determining sensitive species, we test how different parameters like volume filling factor, lower limit of clump mass and mean density affect our assumption of the ISM being clumpy and which of the parameters can constrain clumpiness best. By doing so, we aim to test the strength of subgrid density fluctuations and constrain the parameter space of our model.