The Anatomy of a Star-Forming Galaxy II: the role of FUV heating via dust

TL;DR

This study introduces a novel simulation approach incorporating FUV dust heating via ray-tracing, revealing FUV's role in regulating galaxy structure and star formation, especially in outer disks, when combined with supernova feedback.

Contribution

First to self-consistently include FUV dust heating in galaxy simulations using TREVR, demonstrating its impact on galaxy regulation and structure.

Findings

FUV radiation alone cannot regulate star formation.

FUV produces warm neutral gas and realistic galaxy scale heights.

FUV combined with supernova feedback effectively regulates star formation.

Abstract

Far-Ultraviolet (FUV) radiation greatly exceeds ultraviolet, supernovae and winds in the energy budget of young star clusters but is poorly modeled in galaxy simulations. We present results of the first isolated galaxy disk simulations to include photo-electric heating of gas via dust grains from FUV radiation self-consistently, using a ray-tracing approach that calculates optical depths along the source-receiver sight-line. This is the first science application of the TREVR radiative transfer algorithm. We find that FUV radiation alone cannot regulate star formation. However, FUV radiation produces warm neutral gas and is able to produce regulated galaxies with realistic scale heights. FUV is also a long-range feedback and is more important in the outer disks of galaxies. We also use the super-bubble feedback model, which depends only on the supernova energy per stellar mass, is more physically realistic than common, parameter-driven alternatives and thus better constrains supernova feedback impacts. FUV and supernovae together can regulate star formation without producing too much hot ionized medium and with less disruption to the ISM compared to supernovae alone.