EDP Sciences
Free access
Volume 398, Number 3, February II 2003
Page(s) 857 - 865
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20021652

A&A 398, 857-865 (2003)
DOI: 10.1051/0004-6361:20021652

A 1.2 mm MAMBO/IRAM-30 m study of dust emission from optically luminous $z \approx$ 2 quasars

A. Omont1, A. Beelen2, F. Bertoldi3, P. Cox2, C. L. Carilli4, R. S. Priddey5, R. G. McMahon6 and K. G. Isaak7

1  Institut d'Astrophysique de Paris, CNRS, 98bis boulevard Arago, 75014 Paris, France
2  Institut d'Astrophysique Spatiale, Université de Paris XI, 91405 Orsay, France
3  Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
4  National Radio Astronomy Observatory, PO Box O, Socorro, NM 87801, USA
5  Blackett Laboratory, Imperial College of Science, Technology & Medicine, Prince Consort Road, London SW7 2BW, UK
6  Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
7  Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, UK

(Received 28 June 2002 / Accepted 11 November 2002)

We report 250 GHz (1.2 mm) observations of redshift 1.8 < z < 2.8 optically luminous ( MB < -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 3 $\,\sigma$ flux density limits in the range 1.8 to 4 mJy were obtained. Adopting a typical dust temperature of 45 K, the millimeter emission implies far-infrared luminosities of order $
10^{13} \, L_{\rm\odot}$ and dust masses of $\sim $10 $^8 \,
M_{\rm\odot}$ . Applying a statistical survival analysis to our total sample of 43 detected and 95 undetected quasars at $z \approx 2$ and $z \ga 4$, we find that there is no apparent difference in the far-infrared (FIR) luminosities, hence the star formation rates, of QSOs at $z \approx 2$ 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. 2001). We furthermore find that there is no strong correlation between the far-infrared and optical luminosities, confirming previous results obtained on smaller samples.

Key words: galaxies: formation -- galaxies: starburst -- galaxies: high-redshift -- quasars: general -- cosmology: observations -- submillimeter

Offprint request: A. Omont, omont@iap.fr

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