Properties of Submillimeter Galaxies in a Semi-analytic Model using the
  "Count Matching" Approach: Application to the ECDF-S
  We present a new technique for modeling submillimeter galaxies (SMGs): the
"Count Matching" approach. Using lightcones drawn from a semi-analytic model of
galaxy formation, we choose physical galaxy properties given by the model as
proxies for their submillimeter luminosities, assuming a monotonic
relationship. As recent interferometric observations of the Extended Chandra
Deep Field South show that the brightest sources detected by single-dish
telescopes are comprised by emission from multiple fainter sources, we assign
the submillimeter fluxes so that the combined LABOCA plus bright-end ALMA
observed number counts for this field are reproduced. After turning the model
catalogs given by the proxies into submillimeter maps, we perform a source
extraction to include the effects of the observational process on the recovered
counts and galaxy properties. We find that for all proxies, there are lines of
sight giving counts consistent with those derived from LABOCA observations,
even for input sources with randomized positions in the simulated map.
Comparing the recovered redshift, stellar mass and host halo mass distributions
for model SMGs with observational data, we find that the best among the
proposed proxies is that in which the submillimeter luminosity increases
monotonically with the product between dust mass and SFR. This proxy naturally
reproduces a positive trend between SFR and bolometric IR luminosity. The
majority of components of blended sources are spatially unassociated.
