Simulating the spatial distributions of gas- and ice-phase molecules in galaxies: a new method and preliminary results

TL;DR

This paper introduces a novel simulation method that integrates interstellar chemistry into galaxy-scale models to predict molecular distributions, focusing on gas and ice molecules like H2O and CO2 in galaxies similar to the Milky Way.

Contribution

The paper presents a new simulation framework that combines interstellar chemistry with galaxy evolution models, enabling detailed predictions of molecular abundances and distributions.

Findings

Predicted spatial distributions of H2O, CO, CO2, and CH3OH ices in a Milky Way-like galaxy.

Demonstrated how dust temperature and elemental abundances influence molecular distributions.

Provided preliminary insights into the radial distributions of molecules like PN and PO in the galaxy.

Abstract

Recent observations have revealed significant variations in the abundances of gas- and ice-phase molecules in galaxies with different luminosities and types. In order to discuss the physical origins of these variations, we incorporate gas- and dust-phase interstellar chemistry into galaxy-scale simulations with various baryonic physics including dust formation, evolution, and destruction, all of which are essential for the calculations of 400 interstellar molecule species. The new simulations can accordingly predict the abundances of gas- and ice-phase molecular species such as H_2O and CO_2 ice within individual molecular gas cloud of galaxies based on gas density and temperature, dust temperature (T_dust), elemental abundances (e.g., CHNOPS), UV radiation strength (F_UV), and cosmic ray ionisation rate (zeta_CR) within the clouds. Since this is the first of the series of papers, we describe the details of the new simulations and present the preliminary results focused on the spatial distributions of H_2O, CO, CO_2, and CH_3OH ice species in a disk galaxy similar to the Milky Way. We particularly discuss how T_dust and gas-phase elemental abundances can control the spatial distributions of the above molecules in galaxies. We briefly discuss the total amount of H_2O and CO_2 ices and radial distributions of PN and PO molecules in the Galaxy.