Astron. Astrophys. Suppl. Ser. 135, 83-101

Near infrared observations of quasars with extended ionized envelopes

I. Márquez ^1,2 - F. Durret ^2,3 - P. Petitjean ^2,3

Send offprint request: I. Márquez (isabel@iaa.es)

1 - Instituto de Astrofísica de Andalucía (C.S.I.C.), Apartado 3004, E-18080 Granada, Spain
2 - Institut d'Astrophysique de Paris, CNRS, 98bis Bd. Arago, F-75014 Paris, France
3 - DAEC, Observatoire de Paris, Université Paris VII, CNRS (UA 173), F-92195 Meudon Cedex, France

Received July 17; accepted September 24, 1998

Abstract:

We have observed a sample of 15 and 8 quasars with redshifts between 0.11 and 0.87 (mean value 0.38) in the J and K' bands respectively. Eleven of the quasars were previously known to be associated with extended emission line regions. After deconvolution of the image, substraction of the PSF when possible, and identification of companions with the help of HST archive images when available, extensions are seen for at least eleven quasars. However, average profiles are different from that of the PSF in only four objects, for which a good fit is obtained with an r^1/4 law, suggesting that the underlying galaxies are ellipticals.

Redshifts were available in the literature for surrounding objects in five quasar fields. For these objects, one to five companion galaxies were found. One quasar even belongs to a richness class 1 cluster. Most other quasars in our sample have nearby galaxies in projection which may also be companions. Environmental effects are therefore probably important to account for the properties of these objects.

Key words: galaxies: active -- galaxies: fundamental parameters -- galaxies: interactions -- galaxies: photometry -- quasars: general -- infrared: galaxies