Radio observations of infrared-luminous high-redshift quasi-stellar objects

We present Very Large Array observations at 1.4 and 5 GHz of a sample of 12 quasi-stellar objects (QSOs) at z = 3.99-4.46. The sources were selected a s the brightest sources at 250 GHz from the recent survey of Omont and cowo rkers. We detect seven sources at 1.4 GHz with flux densities S-1.4 greater than or equal to 50 mu Jy. These centimeter wavelength observations imply that the millimeter emission is most likely thermal dust emission. The radi o through optical spectral energy distributions for these sources are withi n the broad range defined by lower redshift, lower optical luminosity QSOs. For two sources, the radio continuum luminosities and morphologies indicat e steep-spectrum, radio-loud emission from a jet-driven radio source. For t he remaining 10 sources, the 1.4 GHz flux densities, or limits, are consist ent with those expected for active star-forming galaxies. If the radio emis sion is powered by star formation in these systems, then the implied star f ormation rates are on the order of 10(3) M-circle dot yr(-1). We discuss th e angular sizes and spatial distributions of the radio-emitting regions, an d we consider briefly these results in the context of coeval black hole and stellar bulge formation in galaxies.