Modelling the 3D physical structure of astrophysical sources with GASS

TL;DR

GASS is a user-friendly 3D modelling tool for astrophysical sources that integrates with radiative transfer codes to simulate and analyze complex star-forming regions in molecular emission.

Contribution

The paper introduces GASS, a novel graphical tool for creating detailed 3D physical models of astrophysical sources, facilitating radiative transfer simulations and analysis.

Findings

GASS effectively generates complex 3D models of star-forming regions.

GASS combined with LIME accurately reproduces observed geometries.

The tool supports analysis of both interferometric and single-dish data.

Abstract

The era of interferometric observations leads to the need of a more and more precise description of physical structures and dynamics of star-forming regions, from pre-stellar cores to protoplanetary discs. The molecular emission can be traced in multiple physical components such as infalling envelopes, outflows and protoplanetary discs. To compare with the observations, a precise and complex radiative transfer modelling of these regions is needed. We present GASS (Generator of Astrophysical Sources Structure), a code that allows us to generate the three-dimensional (3D) physical structure model of astrophysical sources. From the GASS graphical interface, the user easily creates different components such as spherical envelopes, outflows and discs. The physical properties of these components are modelled thanks to dedicated graphical interfaces that display various figures in order to help the user and facilitate the modelling task. For each component, the code randomly generates points in a 3D grid with a sample probability weighted by the molecular density. The created models can be used as the physical structure input for 3D radiative transfer codes to predict the molecular line or continuum emission. An analysis of the output hyper-spectral cube given by such radiative transfer code can be made directly in GASS using the various post-treatment options implemented, such as calculation of moments or convolution with a beam. This makes GASS well suited to model and analyse both interferometric and single-dish data. This paper is focused on the results given by the association of GASS and LIME, a 3D radiative transfer code, and we show that the complex geometry observed in star-forming regions can be adequately handled by GASS+LIME.