An infrared-radio simulation of the extragalactic sky: from the Square
  Kilometer Array to Herschel
  To exploit synergies between the Herschel Space Observatory and next
generation radio facilities, we have extended the semi-empirical extragalactic
radio continuum simulation of Wilman et al. (2008) to the mid- and
far-infrared. Here we describe the assignment of infrared spectral energy
distributions (SEDs) to the star-forming galaxies and active galactic nuclei,
using Spitzer 24, 70 and 160 micron and SCUBA 850 micron survey results as the
main constraints.
  Star-forming galaxies dominate the source counts, and a model in which their
far-infrared-radio correlation and infrared SED assignment procedure are
invariant with redshift underpredicts the observed 24 and 70 micron source
counts. The 70 micron deficit can be eliminated if the star-forming galaxies
undergo stronger luminosity evolution than originally assumed for the radio
simulation, a requirement which may be partially ascribed to known
non-linearity in the far-infrared--radio correlation at low luminosity if it
evolves with redshift. At 24 micron, the shortfall is reduced if the
star-forming galaxies develop SEDs with cooler dust and correspondingly
stronger Polycyclic Aromatic Hydrocarbon (PAH) emission features with
increasing redshift at a given far-infrared luminosity, but this trend may
reverse at z>1 in order not to overproduce the sub-mm source counts. The
resulting model compares favourably with recent BLAST results and we have
extended the simulation database to aid the interpretation of Herschel surveys.
Such comparisons may also facilitate further model refinement and revised
predictions for the SKA and its precursors.
