Abstract
We present initial results from the first deep near-infrared imaging
study of the host galaxies of an extensive sample of low-redshift (z
<0.4) radio-loud and radio-quiet quasars. To minimize selection
effects, the radio-loud and radio-quiet subsamples have been selected to
be indistinguishable in terms of their distributions on the V-z plane,
and classification as radio-loud or radio-quiet is defined in terms of
5-GHz luminosity. We discuss the problems associated with accurate
determination of the infrared point spread function (PSF) and our
adopted solution of an a posteriori selection from a `library' of
observationally determined PSFs. Images reaching surface brightness
levels of μ_K_ = 22 mag arcsec^-2^ of the quasar hosts, before and
after subtraction of the nuclear component, are then presented. After
removal of the nuclear component, the host galaxies of both classes of
quasar are found to be good `standard candles' at K, displaying a K-z
relation identical to that already established for radio galaxies. In
addition, we find no evidence that radio-loud and radio-quiet hosts
differ in terms of K-band luminosity both appear to be selected solely
from the top of the K-band galaxy luminosity function. We briefly
compare the dimensions and near-infrared morphologies of the radio-loud
and radio-quiet hosts and, in the case of radio-loud quasars,
investigate the relationship between near-infrared and radio morphology.
Finally, we give a preliminary discussion of the significance of the
universal incidence of apparent companion objects in our images. A
detailed analysis of the luminosity profiles and companion statistics
derived from the images presented here will be the subject of subsequent
papers.
| Original language | English |
|---|---|
| Pages (from-to) | 455 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 264 |
| Publication status | Published - 1 Sep 1993 |