TY - JOUR
T1 - A survey of z > 5.7 quasars in the sloan digital sky survey. III. Discovery of five additional quasars
AU - Fan, Xiaohui
AU - Hennawi, Joseph F.
AU - Richards, Gordon T.
AU - Strauss, Michael A.
AU - Schneider, Donald P.
AU - Donley, Jennifer L.
AU - Young, Jason E.
AU - Annis, James
AU - Lin, Huan
AU - Lampeitl, Hubert
AU - Lupton, Robert H.
AU - Gunn, James E.
AU - Knapp, Gillan R.
AU - Brandt, W. N.
AU - Anderson, Scott
AU - Bahcall, Neta A.
AU - Brinkmann, Jon
AU - Brunner, Robert J.
AU - Fukugita, Masataka
AU - Szalay, Alexander S.
AU - Szokoly, Gyula P.
AU - York, Donald G.
PY - 2004/8
Y1 - 2004/8
N2 - We present the discovery of five new quasars at z > 5.7, selected from the multicolor imaging data of the Sloan Digital Sky Survey (SDSS). Three of them, at redshifts 5.93, 6.07, and 6.22, were selected from ∼1700 deg 2 of new SDSS Main Survey imaging in the northern Galactic cap. An additional quasar, at redshift 5.85, was discovered by co-adding the data obtained in the Fall Equatorial Stripe in the SDSS Southern Survey Region. The fifth object, at redshift 5.80, is selected from a nonstandard SDSS scan in the southern Galactic cap outside the Main Survey area. The spectrum of SDSS J162331.81+311200.5 (z = 6.22) shows a complete Gunn-Peterson trough at z abs > 5.95, similar to the troughs detected in the other three z ≳ 6.2 quasars known. We present a composite spectrum of the z > 5.7 quasars discovered in the SDSS to date. The average emission-line and continuum properties of z ∼ 6 quasars exhibit no significant evolution compared with those at low redshift. Using a complete sample of nine z > 5.7 quasars, we find that the density of quasars with M 1450 < -26.7 at z ∼ 6 is (6 ± 2) × 10 -10 Mpc -3 (H 0 = 65 km s -1 Mpc -1, Ω = 0.35, and Γ = 0.65), consistent with our previous estimates. The luminosity distribution of the sample is fitted with a power-law luminosity function ψ(L) ∝ L -3.2±0.7, somewhat steeper than but consistent with our previous estimates.
AB - We present the discovery of five new quasars at z > 5.7, selected from the multicolor imaging data of the Sloan Digital Sky Survey (SDSS). Three of them, at redshifts 5.93, 6.07, and 6.22, were selected from ∼1700 deg 2 of new SDSS Main Survey imaging in the northern Galactic cap. An additional quasar, at redshift 5.85, was discovered by co-adding the data obtained in the Fall Equatorial Stripe in the SDSS Southern Survey Region. The fifth object, at redshift 5.80, is selected from a nonstandard SDSS scan in the southern Galactic cap outside the Main Survey area. The spectrum of SDSS J162331.81+311200.5 (z = 6.22) shows a complete Gunn-Peterson trough at z abs > 5.95, similar to the troughs detected in the other three z ≳ 6.2 quasars known. We present a composite spectrum of the z > 5.7 quasars discovered in the SDSS to date. The average emission-line and continuum properties of z ∼ 6 quasars exhibit no significant evolution compared with those at low redshift. Using a complete sample of nine z > 5.7 quasars, we find that the density of quasars with M 1450 < -26.7 at z ∼ 6 is (6 ± 2) × 10 -10 Mpc -3 (H 0 = 65 km s -1 Mpc -1, Ω = 0.35, and Γ = 0.65), consistent with our previous estimates. The luminosity distribution of the sample is fitted with a power-law luminosity function ψ(L) ∝ L -3.2±0.7, somewhat steeper than but consistent with our previous estimates.
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U2 - 10.1086/422434
DO - 10.1086/422434
M3 - Review article
AN - SCOPUS:4544295232
SN - 0004-6256
VL - 128
SP - 515
EP - 522
JO - Astronomical Journal
JF - Astronomical Journal
IS - 2 1784
ER -