Case Studies of Interacting QSO Host Galaxies

Scharwächter, J.; Eckart, A.; Zuther, J.; Pfalzner, S.; Saviane, I.; Ivanov, V. D.; Tacconi-Garman, L. E.; Kotilainen, J. K.; Reunanen, J.; Schödel, R.
The Nuclear Region, Host Galaxy and Environment of Active Galaxies (Eds. Erika Benítez, Irene Cruz-González, & Yair Krongold) Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias) Vol. 32, pp. 155-157 (2008)


The putative interplay of galaxy mergers, starburst activity, and nuclear activity is a key ingredient for the hypothesis of an evolutionary sequence from ultra-luminous infrared galaxies (ULIRGs) to quasi-stellar objects (QSOs). Recent results from a case study of the nearby QSO host I Zw 1, based on near-infrared (NIR) images and spectra taken with ISAAC at the Very Large Telescope (VLT) of the European Southern Observatory (ESO) and on complementary optical images from observations with EFOSC2 at the 3.6 m telescope of ESO, show new indications for an ongoing minor merger between I Zw 1 and the western companion galaxy. First results from NIR imaging of SDSS J114203.40+005135.8 with ISAAC and with the adaptive-optics assisted NAOS CONICA (NACO) Simultaneous Differential Imager (SDI) at the VLT give evidence for a double structure in the center.