Mergers and interactions in Sloan Digital Sky Survey type 2 quasars at z∼ 0.3-0.4. SDSS J143027.66-005614.8: a case study

• Published in: Monthly notices of the Royal Astronomical Society 2012-06, Vol.423 (1), p.80-103
• Main Authors: Villar-Martín, M., Cabrera Lavers, A., Bessiere, P., Tadhunter, C., Rose, M., de Breuck, C.
• Format: Article
• Language: English
• Subjects: Case studies; galaxies: active; galaxies: interactions; Quasars; quasars: general; quasars: individual: SDSS J143027.66–005614.8
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2012.20652.x

We present a compilation of Hubble Space Telescope (HST) images of 58 luminous Sloan Digital Sky Survey (SDSS) type 2 active galactic nuclei (AGNs) at . Of these, 42 are type 2 quasars, which is a good representation of all optically selected SDSS type 2 quasars in this z range. We find that the majority of the host galaxies are ellipticals (30/42 or 71 per cent). This is consistent with studies of radio-loud and radio-quiet type 1 quasars, which show that their host galaxies are, in general, ellipticals. A significant fraction of type 2 quasars (≥25/42 or ≥59 per cent) show clear signatures of morphological disturbance. In most cases, these are clearly identified with merger/interaction processes. We discuss this in the context of related works on type 2 quasars and powerful radio galaxies. We study in detail the particular case of the radio-quiet type 2 quasar SDSS J143027.66-005614.8 at z= 0.318 based on imaging and spectroscopic data from the Very Large Telescope, HST and SDSS. The system shows highly complex morphology, similar to that found in many ultraluminous infrared galaxies, which suggests that it is in the late pre-coalescence stage of a major galaxy merger. The optical continuum spectrum is dominated by a young stellar population of age