Properties of submillimeter galaxies in the CANDELS GOODS-south field

Abstract

We derive physical properties of 10 submillimeter galaxies located in the CANDELS coverage of the GOODS-S field. The galaxies were first identified as submillimeter sources with the LABOCA bolometer and subsequently targeted for 870 m continuum observation with ALMA. The high angular resolution of the ALMA imaging allows secure counterparts to be identified in the CANDELS multiband data set. The CANDELS data provide deep photometric data from UV through near-infrared wavelengths. Using synthetic spectral energy distributions, we derive photometric redshifts, stellar masses, extinction, ages, and the star formation history. The redshift range is z = 1.65-4.76, with two of the galaxies located at z > 4. Two submillimeter galaxy (SMG) counterparts have stellar masses 2-3 orders of magnitude lower than the rest. The remaining SMG counterparts have stellar masses around 1 x 1011 M. The stellar population in the SMGs is typically older than the expected duration of the submillimeter phase, suggesting that the star formation history of SMGs is more complex than a single burst. Non-parametric morphology indices suggest that the SMG counterparts are among the most asymmetric systems compared with galaxies of the same stellar mass and redshift. The Hubble Space Telescope images show that three of the SMGs are associated with ongoing mergers. The remaining counterparts are isolated. Estimating the dust and molecular gas mass from the submillimeter fluxes, and comparing with our stellar masses shows that the gas mass fraction of SMGs is ~28% and that the final stellar mass is likely to be ~(1 - 2) x 1011 M.