[en] The host galaxies of six nearby QSOs are studied on the basis of high-resolution HST optical images and spatially resolved VLT slit spectra. The gas ionization and velocity are mapped as a function of the distance to the central QSO. In the majority of the cases, the QSO significantly contributes to the gas ionization in its whole host galaxy, and sometimes even outside. Reflection or scattering of the QSO H alpha line from remote regions of the galaxy is detected in several instances. The line shifts show that, in all cases, the matter responsible for the light reflection moves away from the QSO, likely accelerated by its radiation pressure. The two faintest QSOs reside in spirals, with some signs of a past gravitational perturbation. One of the intermediate-luminosity QSOs resides in a massive elliptical containing gas ionized (and probably pushed away) by the QSO radiation. The other medium-power object is found in a spiral galaxy displaying complex velocity structure, with the central QSO moving with respect to the bulge, probably as a result of a galactic collision. The two most powerful objects are involved in violent gravitational interactions, and one of them has no detected host. These results suggest that (1) large-scale phenomena, such as galactic collisions, are closely related to the triggering and the feeding of the QSO and (2) once ignited, the QSO has significant influence on its large-scale neighborhood ( often the whole host and sometimes further away).
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Letawe, Yannick ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Magain, Pierre ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Letawe, Géraldine ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Courbin, F.
Hutsemekers, Damien ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Language :
English
Title :
Understanding the relations between QSOs and their host galaxies from combined HST imaging and VLT spectroscopy
Publication date :
2008
Journal title :
Astrophysical Journal
ISSN :
0004-637X
eISSN :
1538-4357
Publisher :
University of Chicago Press, United States - Illinois
Miller, J. S. and Mathews, W. G. 1972, ApJ, 172, 593
Ogle, P. M., et al. 1997, ApJ, 482, L37
Osterbrock, D. E. 1989, Astrophysics of Gazeous Nebulae and Active Galactic Nuclei (Mill Valley: University Science Books)
Sellwood, J. A. 2000, in ASP Con Ser. 197, Dynamics of Galaxies: from the Early Universe to the Present, ed. F. Combes, G. A. Mamon, & V. Charmandaris (San Franciso: ASP), 3
Sanders, D. B., et al. 1988, ApJ, 325, 74
Shields, J. C., & Filippenko, A. V. 1996, A&A, 311, 393
Sijaki, D., et al. 2007, MNRAS, 380, 877
Simpson, J. P., et al. 2002, ApJ, 574, 95
Tran, H. D., et al. 2000, AJ, 120, 562
Tresse, L., et al. 1996, MNRAS, 281, 847
Vanden Berk, D., et al. 2006, AJ, 131, 84
Veilleux, S. 1991, ApJS, 75, 357
Veilleux, S., Osterbrock, E. D.,1987, ApJS, 63, 295