THE ASTRONOMICAL JOURNAL, 121:31È53, 2001 January ( 2001. The American Astronomical Society. All rights reserved. Printed in U.S.A. HIGH-REDSHIFT QUASARS FOUND IN SLOAN DIGITAL SKY SURVEY COMMISSIONING DATA. III. A COLOR-SELECTED SAMPLE AT i* \ 20 IN THE FALL EQUATORIAL STRIPE1 XIAOHUI FAN,2,3 MICHAEL A. STRAUSS,2 GORDON T. RICHARDS,4,5 JEFFREY A. NEWMAN,6 ROBERT H. BECKER,7,8 DONALD P. SCHNEIDER,5 JAMES E. GUNN,2 MARC DAVIS,6 RICHARD L. WHITE,9 ROBERT H. LUPTON,2 JOHN E. ANDERSON,JR.,10 JAMES ANNIS,10 NETA A. BAHCALL,2 ROBERT J. BRUNNER,11 ISTVA  N CSABAI,12 MAMORU DOI,13 MASATAKA FUKUGITA,3,14 G. S. HENNESSY,15 ROBERT B. HINDSLEY,16 GILLIAN R. KNAPP,2 TIMOTHY A. MCKAY,17 JEFFREY A. MUNN,18 Z ‹ ELJKO IVEZIC  ,2 JEFFREY R. PIER,18 ALEXANDER S. SZALAY,12 AND DONALD G. YORK4 Received 2000 August 7 ; accepted 2000 September 12 ABSTRACT This is the third paper in a series aimed at Ðnding high-redshift quasars from Ðve-color (u@g@r@i@z@) imaging data taken along the celestial equator by the Sloan Digital Sky Survey (SDSS) during its com- missioning phase. In this paper, we Ðrst present the observations of 14 bright, high-redshift quasars (3.66 ¹ z ¹ 4.77, discovered in the SDSS fall equatorial stripe, and the SDSS photometry of two i* [ 20) previously known high-redshift quasars in the same region of the sky. Combined with the quasars pre- sented in Paper I and by Schneider et al., we deÐne a color-selected Ñux-limited sample of 39 quasars at 3.6 \ z \ 5.0 and covering a total e†ective area of 182 deg2. From this sample, we estimate the i* [ 20, average spectral power-law slope in the rest-frame UV for quasars at z D 4 to be [0.79 with a standard deviation of 0.34, and the average rest-frame equivalent width of the Lya ] N V emission line to be 69 Ó with a standard deviation of 18 The selection completeness of this multicolor sample is determined Ó. from the model colors of high-redshift quasars, taking into account the distributions of emission-line strengths, intrinsic continuum slope, the line and continuum absorption from intervening material, and the e†ects of photometric errors. The average completeness of this sample is about 75%. The selection function calculated in this paper will be used to correct the incompleteness of this color-selected sample and to derive the high-redshift quasar luminosity function in a companion paper. In an appendix, we present the observations of an additional 18 faint quasars (3.57 ¹ z ¹ 4.80, 20.1 \ i* \ 20.8) discovered in the region on the sky that has been imaged twice. Several quasars presented in this paper exhibit interesting properties, including a radio-loud quasar at z \ 4.77 and a narrow-line quasar (FWHM \ 1500 km s~1) at z \ 3.57. Key words : quasars : general È surveys 1. INTRODUCTION This paper is the third in a series presenting high-redshift (z [ 3.6) quasars selected from the commissioning data of the Sloan Digital Sky Survey (SDSS ; York et al. 2000). In Papers I and II (Fan et al. 1999b, 2000, respectively) in this series, and in Schneider et al. (2000, 2001a, 2001b), we have presented the discovery of D60 quasars at selected z Z 3.6, from B400 deg2 of SDSS multicolor imaging data along the celestial equator. In this paper, we describe observations of additional quasar candidates selected in a similar manner in the fall equatorial stripe, overlapping the areas covered by Paper I and Schneider et al. (2001a), together deÐning a complete color-selected sample of bright high-redshift quasars covering 182 deg2. In addition, we search for fainter ÈÈÈÈÈÈÈÈÈÈÈÈÈÈÈ 1 Based on observations obtained with the Sloan Digital Sky Survey, with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium (ARC), by the W. M. Keck Observatory, which is operated as a scientiÐc partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous Ðnancial support of the W. M. Keck Foundation, and with the Hobby-Eberly Telescope, w• nchen, UniversitatGo ttingen. 2 Princeton University Observatory, Peyton Hall, Princeton, NJ 08544-1001. 3 Institute for Advanced Study, Olden Lane, Princeton, NJ 08540-0631. 4 Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637. 5 Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802. 6 Department of Astronomy, 601 Campbell Hall, University of California, Berkeley, Berkeley, CA 94720-3411. 7 Department of Physics, University of California, Davis, 1 Shields Avenue, Davis, CA 95616. 8 Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory. 9 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218. 10 Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510. 11 Department of Astronomy, 105-24, California Institute of Technology, 1201 East California Boulevard, Pasadena, CA 91125. 12 Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2686. 13 Department of Astronomy and Research Center for the Early Universe, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan. 14 Institute for Cosmic Ray Research, University of Tokyo, 3-2-1 Midori, Tanashi, Tokyo 188-8502, Japan. 15 US Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420. 16 Remote Sensing Division, Code 7215, Naval Research Laboratory, 4555 Overlook Avenue, SW, Washington, DC 20375. 17 Department of Physics, University of Michigan, 500 East University, Ann Arbor, MI 48109-1120. 18 US Naval Observatory, Flagsta† Station, P.O. Box 1149, Flagsta†, AZ 86002. 31