Astron. Astrophys. Suppl. Ser.
Volume 135, Number 1, February II 1999
|Page(s)||83 - 101|
|Published online||15 February 1999|
Near infrared observations of quasars with extended ionized envelopes*
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
Send offprint request to: I. Márquez
Accepted: 24 September 1998
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 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 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
Based on data obtained at the European Southern Observatory, La Silla, Chile. Also based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute; STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France and of the NASA/IPAC extragalactic database (NED), which is operated by the Jet Propulsion Laboratory, Caltech under contract with the National Aeronautics and Space Administration.
© European Southern Observatory (ESO), 1999