  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.
