Photometric redshifts of quasars

We demonstrate that the design of the Sloan Digital Sky Survey (SDSS) filte r system and the quality of the SDSS imaging data are sufficient for determ ining accurate and precise photometric redshifts of quasars. Using a sample of 2625 quasars, we show that "photo-z" determination is even possible for z less than or equal to2.2 despite the lack of a strong continuum break, w hich robust photo-z techniques normally require. We find that, using our em pirical method on our sample of objects known to be quasars, approximately 70% of the photometric redshifts are correct to within Deltaz = 0.2; the fr action of correct photometric redshifts is even better for z >3. The accura cy of quasar photometric redshifts does not appear to be dependent upon mag nitude to nearly 21st magnitude in i'. Careful calibration of the color-red shift relation to 21st magnitude may allow for the discovery of similar to 10(6) quasar candidates in addition to the 10(5) quasars that the SDSS will confirm spectroscopically. We discuss the efficient selection of quasar ca ndidates from imaging data for use with the photometric redshift technique and the potential scientific uses of a large sample of quasar candidates wi th photometric redshifts.