Grid of Lya radiation transfer models for the interpretation of distant galaxies

TL;DR

This paper presents a comprehensive grid of 3D radiation transfer models for Lya and UV continuum in star-forming galaxies, aiding interpretation of distant galaxy observations and advancing modeling techniques.

Contribution

It introduces an extensive set of 6240 improved Monte Carlo radiation transfer models covering diverse parameters for Lya and UV radiation in galaxy environments.

Findings

Lya escape fraction depends strongly on dust, HI, and velocity.

Line profiles exhibit diverse morphologies, from absorption to complex emission.

Models are publicly available for broader scientific use.

Abstract

Lya is a key diagnostic for numerous observations of distant star-forming galaxies. It's interpretation requires, however, detailed radiation transfer models. We provide an extensive grid of 3D radiation transfer models simulating the Lya and UV continuum radiation transfer in the interstellar medium of star-forming galaxies. We have improved our Monte Carlo MCLya code, and have used it to compute a grid of 6240 radiation transfer models for homogeneous spherical shells containing HI and dust surrounding a central source. The simulations cover a wide range of parameter space. We present the detailed predictions from our models including in particular the Lya escape fraction fesc, the continuum attenuation, and detailed Lya line profiles. The Lya escape fraction is shown to depend strongly on dust content, but also on other parameters (HI column density and radial velocity). The predicted line profiles show a great diversity of morphologies ranging from broad absorption lines to emission lines with complex features. The results from our simulations are distributed in electronic format. Our models should be of use for the interpretation of observations from distant galaxies, for other simulations, and should also serve as an important base for comparison for future, more refined, radiation transfer models.