A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II. Discovery of three additional quasars at z

article A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II. Discovery of three additional quasars at z > 6 published yes Xiaohui Fan author Michael A. Strauss author Donald P. Schneider author Robert H. Becker author Richard L. White author Zoltán Haiman author 7c006e8c-cc0d-11ee-8322-cb904ef76f36 Michael Gregg author Laura Pentericci author Eva K. Grebel author Vijay K. Narayanan author Yeong-Shang Loh author Gordon T. Richards author James E. Gunn author Robert H. Lupton author Gillian R. Knapp author Željko Ivezić author W. N. Brandt author Matthew Collinge author Lei Hao author Daniel Harbeck author Francisco Prada author Joop Schaye author Iskra Strateva author Nadia Zakamska author Scott Anderson author Jon Brinkmann author Neta A. Bahcall author Don Q. Lamb author Sadanori Okamura author Alex Szalay author Donald G. York author We present the discovery of three new quasars at z>6 in 1300 deg^2 of SDSS imaging data, J114816.64+525150.3 (z=6.43), J104845.05+463718.3 (z=6.23) and J163033.90+401209.6 (z=6.05). The first two objects have weak Ly alpha emission lines; their redshifts are determined from the positions of the Lyman break. They are only accurate to 0.05 and could be affected by the presence of broad absorption line systems. The last object has a Ly alpha strength more typical of lower redshift quasars. Based on a sample of six quasars at z>5.7 that cover 2870 deg^2 presented in this paper and in Paper I, we estimate the comoving density of luminous quasars at z 6 and M_{1450} < -26.8 to be (8 +/- 3)x10^{-10} Mpc^{-3} (for H_0 = 50 km/s/Mpc, Omega = 1). HST imaging of two z>5.7 quasars and high-resolution ground-based images (seeing 0.4'') of three additional z>5.7 quasars show that none of them is gravitationally lensed. The luminosity distribution of the high-redshfit quasar sample suggests the bright end slope of the quasar luminosity function at z 6 is shallower than Psi L^{-3.5} (2-sigma), consistent with the absence of strongly lensed objects. American Astronomical Society2003 eng The Astronomical Journal 0004-6256 1538-388110.1086/368246 12541649-1659 yes Fan, Xiaohui, Michael A. Strauss, Donald P. Schneider, Robert H. Becker, Richard L. White, Zoltán Haiman, Michael Gregg, et al. “A Survey of z > 5.7 Quasars in the Sloan Digital Sky Survey. II. Discovery of Three Additional Quasars at z > 6.” The Astronomical Journal. American Astronomical Society, 2003. <a href="https://doi.org/10.1086/368246">https://doi.org/10.1086/368246</a>. Fan, X., Strauss, M. A., Schneider, D. P., Becker, R. H., White, R. L., Haiman, Z., … York, D. G. (2003). A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II. Discovery of three additional quasars at z > 6. The Astronomical Journal. American Astronomical Society. <a href="https://doi.org/10.1086/368246">https://doi.org/10.1086/368246</a> Fan, Xiaohui, et al. “A Survey of z > 5.7 Quasars in the Sloan Digital Sky Survey. II. Discovery of Three Additional Quasars at z > 6.” The Astronomical Journal, vol. 125, no. 4, American Astronomical Society, 2003, pp. 1649–59, doi:<a href="https://doi.org/10.1086/368246">10.1086/368246</a>. X. Fan, M.A. Strauss, D.P. Schneider, R.H. Becker, R.L. White, Z. Haiman, M. Gregg, L. Pentericci, E.K. Grebel, V.K. Narayanan, Y.-S. Loh, G.T. Richards, J.E. Gunn, R.H. Lupton, G.R. Knapp, Ž. Ivezić, W.N. Brandt, M. Collinge, L. Hao, D. Harbeck, F. Prada, J. Schaye, I. Strateva, N. Zakamska, S. Anderson, J. Brinkmann, N.A. Bahcall, D.Q. Lamb, S. Okamura, A. Szalay, D.G. York, The Astronomical Journal 125 (2003) 1649–1659. Fan X, Strauss MA, Schneider DP, et al. A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II. Discovery of three additional quasars at z > 6. The Astronomical Journal. 2003;125(4):1649-1659. doi:<a href="https://doi.org/10.1086/368246">10.1086/368246</a> Fan X, Strauss MA, Schneider DP, Becker RH, White RL, Haiman Z, Gregg M, Pentericci L, Grebel EK, Narayanan VK, Loh Y-S, Richards GT, Gunn JE, Lupton RH, Knapp GR, Ivezić Ž, Brandt WN, Collinge M, Hao L, Harbeck D, Prada F, Schaye J, Strateva I, Zakamska N, Anderson S, Brinkmann J, Bahcall NA, Lamb DQ, Okamura S, Szalay A, York DG. 2003. A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II. Discovery of three additional quasars at z > 6. The Astronomical Journal. 125(4), 1649–1659. X. Fan et al., “A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II. Discovery of three additional quasars at z > 6,” The Astronomical Journal, vol. 125, no. 4. American Astronomical Society, pp. 1649–1659, 2003. 177502024-09-06T09:38:08Z2024-09-30T07:33:02Z