First results from the Isaac Newton Telescope Wide Angle Survey: The z>5 quasar survey

We report the first results of an observational program designed to determine the luminosity density of high redshift quasars (z > 5 quasars) using deep multi-colour CCD data. We report the discovery and spectra of 3 i < 21.5 high redshift (z > 4.4) quasars, including one with z > 5. At z=5.17, this is the fourth highest redshift quasar currently published. Using these preliminary results we derive an estimate of the M \rm_B < - 25.0 (M \rm_{AB1450} < - 24.5) quasar space density in the redshift range 4.8 < z < 5.8 of 3.6 \pm2.5\times 10^{-8} \Mpc ^{-3} . When completed the survey will provide a firm constraint on the contribution to the ionizing UV background in the redshift range 4.5 - 5.5 from quasars by determining the faint end slope of the quasar luminosity function. The survey uses imaging data taken with the 2.5m Isaac Newton Telescope as part of the Public Isaac Newton Group Wide Field Survey (WFS). This initial sample of objects is taken from two fields of effective area $\sim 12.5deg ^2$ from the final $\sim 100deg ^2$.