A unified empirical model for infrared galaxy counts based on observed
  physical evolution of distant galaxies
  We reproduce the mid-infrared to radio galaxy counts with a new empirical
model based on our current understanding of the evolution of main-sequence (MS)
and starburst (SB) galaxies. We rely on a simple Spectral Energy Distribution
(SED) library based on Herschel observations: a single SED for the MS and
another one for SB, getting warmer with redshift. Our model is able to
reproduce recent measurements of galaxy counts performed with Herschel,
including counts per redshift slice. This agreement demonstrates the power of
our 2 Star-Formation Modes (2SFM) decomposition for describing the statistical
properties of infrared sources and their evolution with cosmic time. We discuss
the relative contribution of MS and SB galaxies to the number counts at various
wavelengths and flux densities. We also show that MS galaxies are responsible
for a bump in the 1.4 GHz radio counts around 50 {\mu}Jy. Material of the model
(predictions, SED library, mock catalogs...) is available online at
http://irfu.cea.fr/Sap/Phocea/Page/index.php?id=537.
