Abstract

Poster - Splinter GalaxyEvol

Thursday, 12 September 2024, 15:42   (S21)

Decoding Dense Gas with 3D MHD Simulations: Molecular Signatures in Galactic Star Formation

Oerd Xhemollari, Daniel Seifried
I. Physics Institute, University of Cologne

Giant molecular clouds, the birthplaces of massive stars and clusters, contain dense clumps and filamentary structures that serve as crucial nurseries. To understand the channeling of material from parsec scales to individual stars, we aim to characterize key gas properties like density, temperature, and particularly the chemical composition across all scales in molecular clouds. Here, we present the non-equilibrium abundance of various molecules so far unexplored in 3D MHD simulations. For this, we chemically post-process tracer particles modeled in the SILCC-Zoom simulations with a novel astrochemistry pipeline from Panessa et al. 2023. We use the publicly available, most recent network from the astrochemical database KIDA, which includes over 8000 reactions and 557 species. Focusing on nitrogen- and sulfur-bearing species, we explore for the first time their potential as dense-gas tracers under dynamically changing conditions. Specifically, we present spatial and temporal correlations between species (e.g., CS, HCN, N2H+). We investigate to what extent the HCN-HNC ratio can be used as a “chemical” temperature probe. Motivated by recent observations, we examine the HCN/CO ratio and discuss its accuracy in tracing the fraction of dense gas. We extend this novel analysis technique of exploring the chemical properties of the ISM to a wide range of environmental conditions, by varying factors such as gas metallicity and UV and cosmic ray flux. This can provide invaluable input for analyzing and interpreting modern observations of the ISM in various environments