High-redshift quasars found in Sloan Digital Sky Survey commissioning data

We present photometric and spectroscopic observations of 15 high-redshift q uasars (z > 3.6) discovered from similar to 140 deg(2) of five-color (u', g ', r', i', and z') imaging data taken by the Sloan Digital Sky Survey (SDSS ) during its commissioning phase. The quasars are selected by their distinc tive colors in SDSS multicolor space. Four of the quasars have redshifts hi gher than 4.6 (z = 4.63, 4.75, 4.90, and 5.00, the latter being the highest redshift quasar yet known). In addition, two previously known z > 4 object s were recovered from the data. The quasars all have i* < 20 and have lumin osities comparable to that of 3C 273. The spectra of the quasars have simil ar features (strong, broad emission lines and substantial absorption bluewa rd of the Ly alpha emission line) seen in previously known high-redshift qu asars. Although the photometric accuracy and image quality fail to meet the final survey requirements, our success rate for identifying high-redshift quasars (17 quasars from 27 candidates) is much higher than that of previou s multicolor surveys. However, the numbers of high-redshift quasars found i s in close accord with the number density inferred from previous surveys.