SIMBAD references

We report 250GHz (1.2mm) observations of redshift 1.8<z<2.8 optically luminous (M_B<27.0), radio quiet quasars using the Max-Planck Millimeter Bolometer (MAMBO) array at the IRAM 30-metre telescope. Nine quasars were detected and for 26 quasars 3σ flux density limits in the range 1.8 to 4mJy were obtained. Adopting a typical dust temperature of 45K, the millimeter emission implies far-infrared luminosities of order 10¹³L_☉ and dust masses of ∼10⁸M_☉. Applying a statistical survival analysis to our total sample of 43 detected and 95 undetected quasars at z≃2 and z>4, we find that there is no apparent difference in the far-infrared (FIR) luminosities, hence the star formation rates, of QSOs at z≃2 and at 3.6<z<5. This differs from radio galaxies, for which the FIR luminosity was found to increase with redshift (Archibald et al., 2001MNRAS.323..417A). We furthermore find that there is no strong correlation between the far-infrared and optical luminosities, confirming previous results obtained on smaller samples.