Radio observations of z≈2 luminous QSOs

Abstract

We present Very Large Array observations at 1.4 and 5 GHz of a sample of 16 quasi-stellar objects (QSOs) at z = 1.78 to 2.71. These sources were chosen to have similar optical properties (M_B, spectra) as samples of (z ≥ 3.7 QSOs) for which we have comparable (sub)millimeter (250 GHz or 350 GHz) and centimeter observations. Half of the chosen quasars are bright at 250 or 350 GHz while the other half have not been detected at (sub)mm wavelengths. All eight submm-loud sources in our study were detected at 1.4 GHz, the majority of these at high significance (≥0.2±0.02 mJy). Only three of the submm-quiet QSO's were detected at radio frequencies, and these at lower significance (≤0.17 mJy). These results argue for a real physical difference between the submm-luminous and submm-quiet sources, and against a continuum of submm luminosities. Four of these sources have radio spectral indices and radio-to-FIR ratios consistent with star forming galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html