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Astron. Astrophys. 318, 15-18 (1997)

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2.2 and 1300 µm observations of a complete sample of southern quasars

R. Chini 1, E. Kreysa 1 and W.F. Wargau 1, 2

1 Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
2 UNISA, Dept. of Mathematics, A/ Mathematics and Astronomy, Pretoria, South-Africa

Received 14 July 1995 / Accepted 14 June 1996


We present 2.2 and 1300 µm data of a complete sample of optically selected southern quasars. All objects have 1300 µm flux densities below [FORMULA] mJy ([FORMULA]), except QSO 0448-392 which shows a faint signal of [FORMULA] mJy. These results clearly indicate that previously claimed detections at Jy level must have been erroneous. The 2.2 µm data allow the determination of the spectral turnover at short wavelengths and define the spectral slope between IR and radio wavelengths. The sample can be divided into two categories of 7 radio-loud and 10 radio-quiet quasars. The radio-loud quasars have redshifts between [FORMULA] and 3.2 and their energy distributions do not differ significantly from nearby quasars; the emission from cm to mm wavelengths is due to synchrotron radiation. The analysis of the radio-quiet quasars does not show any conclusive evidence for thermal components apart from QSO 0530-379 where the FIR emission is probably dominated by thermal radiation from dust.

Key words: galaxies: ISM – quasars: general – infrared: galaxies – radio continuum: galaxies – radiation mechanisms: non thermal

Send offprint requests to: R. Chini

© European Southern Observatory (ESO) 1997

Online publication: July 8, 1998