Beelen, A.; Cox, P.; Benford, D.J.; Dowell, C.D.; Kovacs, A.; Bertoldi, F.; Omont, A.; Carilli, C.L.

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 ($$0.6$$ to $$2.2~\times~10^{13}\ \mathrm{L_\odot}$$). The combined mean spectral energy distribution (SED) of all high-redshift quasars with two or more rest frame far-infrared photometric measurements is best fit with a greybody with temperature of 47 ± 3 K and a dust emissivity power-law spectral index of $$\beta~=~1.6~\pm~0.1$$. 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.

Accepted for publication in ApJ, Volumne 642, Issue 2, pp. 694-701. Find this paper on ADS under the reference 2006ApJ...642..694B, or on the arXiv service under the reference astro-ph/0603121.

• Fits files produced by CRUSH for the 350 µm observations made with SHARC II of the 6 sources published in this paper