The evolution of Radio Loud Quasar host galaxies: AO observations at z = 3
R. Falomo, J.K. Kotilainen, R. Scarpa, A. Treves, M. Uslenghi
Abstract
We report on ESO--VLT adaptive optics imaging of one radio-loud quasar at z
∼
3. In spite of the large distance of the object we are able to detect its surrounding extended nebulosity the properties of which are consistent with an underlying massive galaxy of M
K
∼
--27 and effective radius R
e
= 7 kpc. As far as we know this is the clearest detection of a radio loud quasar host at high redshift. The host luminosity is indicative of the existence of massive spheroids even at this early cosmic epoch. The host luminosity is about 1 magnitude fainter than the expected value based on the average trend of the host galaxies of RLQ at lower redshift. The result, which however is based on a single object, suggests that at z
∼
3 there is a deviation from a luminosity--redshift dependence regulated only by passive evolution.