Influence of turbulence on Lyman-alpha scattering

TL;DR

This paper introduces a Monte Carlo radiative transfer model to analyze how turbulence with finite correlation length impacts Lyman-alpha photon scattering in neutral hydrogen, revealing significant effects on photon escape and scattering behavior.

Contribution

The study presents a novel Monte Carlo code that incorporates turbulence with finite correlation length to examine its influence on Lyman-alpha radiative transfer.

Findings

Correlation length significantly affects Lyα scattering properties.

Turbulence can reduce the number of scatterings by orders of magnitude.

Effective mean free path of photons is altered by turbulence.

Abstract

We develop a Monte Carlo radiative transfer code to study the effect of turbulence with a finite correlation length on scattering of Lyman-alpha (Ly$\alpha$) photons propagating through neutral atomic hydrogen gas. We investigate how the effective mean free path, the emergent spectrum, and the average number of scatterings that Ly$\alpha$ photons experience change in the presence of turbulence. We find that the correlation length is an important and sensitive parameter that has an influence on physically relevant properties of Ly$\alpha$ radiative transfer. In particular, it can significantly, by orders of magnitude, reduce the number of scattering events that the average Ly$\alpha$ photon undergoes before it escapes the turbulent cloud.