6. Concluding remarks
We have presented observations of the rest-frame far-infrared continuum of a small sample of radio-loud AGN (4 radio galaxies and 3 quasars) with .
One of the main findings is the detection of thermal continuum emission from the radio galaxy MG 1019+0535 (). This is particularly important since it confirms the suggestion that its weak Ly emission is probably due to dust extinction. We attempt to estimate the temperature of the dust in order to derive the dust total mass, but the present data data do not allow us to constrain stringently the range of possible temperatures. However, we estimate that the total dust mass should be of order M for temperatures K. The overall rest-frame UV-FIR SED can be accounted for by a relatively evolved host galaxy (age 0.8 Gyr) experiencing an episode of vigorous star formation.
The radio galaxy 1243+036 (), on the other hand, seems to have a lower amount of dust and molecular gas than those active galaxies that have so far been detected at high redshifts, indicating that the properties of the ISM in active objects at can be rather inhomogeneous.
Finally, the three flat-spectrum radio-loud quasars () observed at 1.3 mm show evidence of a spectral turnover at high frequencies. Our data do not allow us to understand what fraction of the turnover is due to the effects of variability, but we conclude that variability cannot be the only cause.
© European Southern Observatory (ESO) 1998
Online publication: December 8, 1997