A 1.2 mm MAMBO/IRAM-30 m survey of dust emission from the highest redshift PSS quasars

We report 250 GHz (1.2 mm) observations of redshift greater than or equal to3.8 quasars from the Palomar Sky Survey (PSS) sample, using the Max-Planck Millimetre Bolometer (MAMBO) array at the IRAM 30-metre telescope. Eighteen sources were detected and upper limits were obtained for 44 with 3 sigma flux density limits in the range 1.5-4 mJy. Adopting typical dust temperatures of 40-50 K, we derive dust masses of a few 10(8) M-circle dot and far-infrared luminosities of order 10(13) L-circle dot. We suggest that a substantial fraction of this luminosity arises from young stars, implying star formation rates approaching 10(3) M-circle dot yr(-1) or more. The high millimetre detection rate supports current views on a connection between AGN and star forming activity, suggesting a parallel evolution of the central black hole and of the stellar core of a galaxy, although their growth-rate ratio seems higher than the mass ratio observed in nearby galaxies. The observed, exceptionally bright objects may trace the peaks of the primordial density field, the cores of future giant ellipticals.