VLT adaptive optics imaging of QSO host galaxies and their close environment at z 2.5: Results from a pilot program

¹ INAF - Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy e-mail: falomo@pd.astro.it
² Tuorla Observatory, University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland e-mail: jarkot@utu.fi
³ European Southern Observatory, 3107 Alonso de Cordova, Santiago, Chile e-mail: rscarpa@eso.org
⁴ Università dell'Insubria, via Valleggio 11, 22100 Como, Italy e-mail: treves@mib.infn.it

Received: 25 August 2004
Accepted: 3 December 2004

Abstract

We report on ESO–VLT near-IR adaptive optics imaging of one radio-loud (PKS 0113-283) and two radio quiet (Q 0045-3337 and Q 0101-337) quasars at . In the first case we are able to resolve the QSO and find that it is hosted by an elliptical of absolute magnitude M_K = -27.6. For the other two objects no extended emission has been unambiguously detected. This result, although restricted to a single object, extends up to the finding that cosmic evolution of radio-loud quasar hosts follows the trend expected for luminous and massive spheroids undergoing passive evolution. For Q 0045-3337 our high resolution images show that it is located 1.2 arcsec from a foreground disc galaxy, which may act as a gravitational lens, since the QSO most probably lies within the galaxy Einstein radius.