2008MNRAS.386..819O

We report Cousins R-band monitoring of the high-redshift (z = 4.40) radio-quiet quasar Q2203+292 from 1999 May to 2007 October. The quasar shows maximum peak-to-peak light curve amplitude of ∼0.3 mag during the time of our monitoring, and ∼0.9 mag when combined with older literature data. The rms of a fit to the light curve with a constant is 0.08 and 0.2 mag, respectively. The detected changes are at ∼3σ level. The quasar was in a stable state during the recent years and it might have undergone a brightening event in the past. The structure function analysis concluded that the object shows variability properties similar to those of the lower redshift quasars. We set a lower limit to the Q2203+292 broad-line region mass of 0.3-0.4M_solar. Narrow-band imaging search for redshifted Lyα from other emission-line objects at the same redshift shows no emission-line objects in the quasar vicinity.