2006ApJ...642..694B

We report detections of six high-redshift (1.8≤z≤6.4), optically luminous, radio-quiet quasars at 350 µm, using the SHARC II bolometer camera at the Caltech Submillimeter Observatory. Our observations double the number of high-redshift quasars for which 350 µm photometry is available. By combining the 350 µm measurements with observations at other submillimeter/millimeter wavelengths, for each source we have determined the temperature of the emitting dust (ranging from 40 to 60 K) and the far-infrared luminosity [0.6-2.2x10¹³ L_☉]. The combined mean spectral energy distribution of all high-redshift quasars with two or more rest-frame far-infrared photometric measurements is best fit with a graybody with temperature of 47±3 K and a dust emissivity power-law spectral index of β=1.6±0.1. This warm dust component is a good tracer of the starburst activity of the quasar host galaxy. The ratio of the far-infrared to radio luminosities of infrared-luminous, radio-quiet high-redshift quasars is consistent with that found for local star-forming galaxies.