Slit and integral-field optical spectroscopy of the enigmatic quasar HE 0450–2958 ^*

¹ Institut d'Astrophysique et Géophysique, Université de Liège, Allée du 6 Août, 17 Bâtiment B5C, 4000 Liège, Belgium e-mail: gletawe@ulg.ac.be
² Laboratoire d'Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, 1290 Sauverny, Switzerland

Received: 24 September 2007
Accepted: 3 December 2007

Abstract

Context.Interest in the quasar HE 0450-2958 arose following the publication of the non-detection of its expected massive host, leading to various interpretations.

Aims.This article investigates the gaseous and stellar contents of the system through additional VLT/FORS slit spectra and integral field spectroscopy from VLT/VIMOS.

Methods.We apply our MCS deconvolution algorithm on slit spectra for the separation of the QSO and diffuse components, and develop a new method to remove the point sources in Integral Field Spectra, allowing extraction of velocity maps, narrow-line images, spatially resolved spectra or ionization diagrams of the surroundings of HE 0450–2958.

Results.The whole system is embedded in gas, mostly ionized by the QSO radiation field and shocks associated with radio jets. The observed gas and star dynamics are unrelated, revealing a strongly perturbed system. Despite longer spectroscopic observations, the host galaxy remains undetected.