Photon Feedback: Screening and the Eddington Limit

TL;DR

This paper investigates why bright star-forming galaxies, including high-redshift ULIRGs and local starbursts, radiate below their Eddington Limit, showing that radiation pressure on dust is not the dominant factor in their large-scale gas dynamics.

Contribution

It introduces a simple radiative transfer model demonstrating that radiation pressure on dust is insufficient to significantly influence galaxy-scale gas dynamics.

Findings

High-redshift ULIRGs radiate at two orders of magnitude below the Eddington Limit.

Local starbursts like M82 and Arp 220 radiate at a few percent of the Eddington Limit.

Radiation pressure on dust does not substantially affect large-scale gas movements in star-forming galaxies.

Abstract

Bright star-forming galaxies radiate well below their Eddington Limit. The value of the flux-mean opacity that mediates the radiation force onto matter is orders of magnitude smaller than the UV or optical dust opacity. On empirical grounds, it is shown that high-redshift ULIRGs radiate at two orders of magnitude below their Eddington Limit, while the local starbursters M82 and Arp 220 radiate at a few percent of their Eddington Limit. A simple model for the radiative transfer of UV and optical light in dust-rich environments is considered. Radiation pressure on dust does not greatly affect the large-scale gas dynamics of star-forming galaxies.