Rj. Mclure et al., Two-dimensional modelling of optical Hubble Space Telescope and infrared tip-tilt images of quasar host galaxies, M NOT R AST, 318(3), 2000, pp. 693-702
A description is given of the method used to extract quasar host-galaxy par
ameters from the deep Hubble Space Telescope (HST) quasar images presented
by McLure, Dunlop and co-workers. We then give the results of extensive tes
ting of this technique on a wide range of simulated quasar+host combination
s spanning the redshift range of our HST study (0.1 <z <0.3). These simulat
ions demonstrate that, when applied to our deep HST images, our method of a
nalysis can easily distinguish the morphological type of a given host galax
y, and determine its scalelength, luminosity, axial ratio and position angl
e to within an accuracy of a few per cent. We also present new infrared tip
-tilt images of four of the most luminous quasars in our HST sample, along
with the outcome of modelling these data in a similar manner. The results p
rovide further confidence in the accuracy of the derived host-galaxy scalel
engths, and allow an accurate determination of R-K colours for this subset
of sources. All four of these quasar host galaxies have very similar red co
lours, R-K=2.9 +/-0.2, indicative of a well-evolved stellar population.