A panchromatic view of star cluster formation in a simulated dwarf
  galaxy starburst
  We present a photometric analysis of star and star cluster (SC) formation in
a high-resolution simulation of a dwarf galaxy starburst that allows the
formation of individual stars to be followed. Previous work has demonstrated
that the properties of the SCs formed in the simulation are in good agreement
with observations. In this paper, we create mock spectral energy distributions
and broad-band photometric images using the radiative transfer code SKIRT 9. We
test several observational star formation (SF) tracers and find that
$24\,\mu$m, total infrared and H$_\alpha$ trace the underlying SF rate during
the (post)starburst phase, while UV tracers yield a more accurate picture of
star formation during quiescent phases prior to and after the merger. We then
place the simulated galaxy at distances of $10$ and $50$ Mpc and use aperture
photometry at Hubble Space Telescope resolution to analyse the simulated SC
population. During the starburst phase, a hierarchically forming set of SCs
leads inaccurate source separation because of crowding. This results in
estimated SC mass function slopes that are up to $\sim0.3$ shallower than the
true slope of $\sim-2$ found for the bound clusters identified from the
particle data in the simulation. The masses of the largest clusters are
overestimated by a factor of up to $2.5$ due to unresolved clusters within the
apertures. The aperture-based analysis also produces a relation between cluster
formation efficiency and SF rate surface density that is flatter than that
recovered from bound clusters. The differences are strongest in quiescent SF
environments.
