Dust emission from high-redshift QSOs

We present detections of emission at 250 GHz (1.2 mm) from two high-redshif t QSOs from the Sloan Digital Sky Survey sample using the bolometer array a t the IRAM 30 m telescope. The sources are SDSSp 015048.83+004126.2 at z = 3.7 and SDSSp J033829.31+002156.3 at z = 5.0; the latter is the third highe st redshift QSO known and the highest redshift millimeter-emitting source y et identified. We also present deep radio continuum imaging of these two so urces at 1.4 GHz using the Very Large Array. The combination of centimeter and millimeter observations indicate that the 250 GHz emission is most like ly thermal dust emission, with implied dust masses approximate to 10(8) M.. We consider possible dust heating mechanisms, including UV emission from t he active galactic nucleus (AGN) and a massive starburst concurrent with th e AGN, with implied star formation rates greater than 10(3) M. yr(-1).