A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II - Discovery of three additional quasars at z > 6

Xiaohui Fan, Michael A. Strauss, Donald P. Schneider, Robert H. Becker, Richard L. White, Zolt́an Haiman, Michael Gregg, Laura Pentericci, Eva K. Grebel, Vijay K. Narayanan, Yeong Shang Loh, Gordon T. Richards, James E. Gunn, Robert H. Lupton, Gillian R. Knapp, Željko Ivezić, W. N. Brandt, Matthew Collinge, Lei Hao, Daniel HarbeckFrancisco Prada, Joop Schaye, Iskra Strateva, Nadia Zakamska, Scott Anderson, Jon Brinkmann, Neta A. Bahcall, Don Q. Lamb, Sadanori Okamura, Alex Szalay, Donald G. York

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Abstract

We present the discovery of three new quasars at z > 6 in ∼ 1300 deg2 of Sloan Digital Sky Survey 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 Lyα 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 Lyα strength more typical of lower redshift quasars. Based on a sample of six quasars at z > 5.7 that cover 2870 deg2 presented in this paper and in Paper I, we estimate the comoving density of luminous quasars at z ∼ 6 and M1450 < -26.8 to be (8 ± 3) × 10-10 Mpc-3 (for H 0 = 50 km s-1 Mpc-1, Ω = 1). Hubble Space Telescope 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-redshift quasar sample suggests the bright-end slope of the quasar luminosity function at z ∼ 6 is shallower than ψ ∝ L-3.5 (2 σ), consistent with the absence of strongly lensed objects.

Original languageEnglish (US)
Pages (from-to)1649-1659
Number of pages11
JournalAstronomical Journal
Volume125
Issue number4 1768
DOIs
StatePublished - Apr 2003

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quasars
luminosity
slopes
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estimates

Keywords

  • Gravitational lensing
  • Quasars: absorption lines
  • Quasars: emission lines quasars: general

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

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. Astronomical Journal, 125(4 1768), 1649-1659. https://doi.org/10.1086/368246

A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II - Discovery of three additional quasars at z > 6. / Fan, Xiaohui; Strauss, Michael A.; Schneider, Donald P.; Becker, Robert H.; White, Richard L.; Haiman, Zolt́an; Gregg, Michael; Pentericci, Laura; Grebel, Eva K.; Narayanan, Vijay K.; Loh, Yeong Shang; Richards, Gordon T.; Gunn, James E.; Lupton, Robert H.; Knapp, Gillian R.; Ivezić, Željko; Brandt, W. N.; Collinge, Matthew; Hao, Lei; Harbeck, Daniel; Prada, Francisco; Schaye, Joop; Strateva, Iskra; Zakamska, Nadia; Anderson, Scott; Brinkmann, Jon; Bahcall, Neta A.; Lamb, Don Q.; Okamura, Sadanori; Szalay, Alex; York, Donald G.

In: Astronomical Journal, Vol. 125, No. 4 1768, 04.2003, p. 1649-1659.

Research output: Contribution to journalArticle

Fan, X, Strauss, MA, Schneider, DP, Becker, RH, White, RL, Haiman, Z, Gregg, M, Pentericci, L, Grebel, EK, Narayanan, VK, Loh, YS, 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', Astronomical Journal, vol. 125, no. 4 1768, pp. 1649-1659. https://doi.org/10.1086/368246
Fan, Xiaohui ; Strauss, Michael A. ; Schneider, Donald P. ; Becker, Robert H. ; White, Richard L. ; Haiman, Zolt́an ; Gregg, Michael ; Pentericci, Laura ; Grebel, Eva K. ; Narayanan, Vijay K. ; Loh, Yeong Shang ; Richards, Gordon T. ; Gunn, James E. ; Lupton, Robert H. ; Knapp, Gillian R. ; Ivezić, Željko ; Brandt, W. N. ; Collinge, Matthew ; Hao, Lei ; Harbeck, Daniel ; Prada, Francisco ; Schaye, Joop ; Strateva, Iskra ; Zakamska, Nadia ; Anderson, Scott ; Brinkmann, Jon ; Bahcall, Neta A. ; Lamb, Don Q. ; Okamura, Sadanori ; Szalay, Alex ; York, Donald G. / A survey of z > 5.7 quasars in the Sloan Digital Sky Survey. II - Discovery of three additional quasars at z > 6. In: Astronomical Journal. 2003 ; Vol. 125, No. 4 1768. pp. 1649-1659.
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AU - Fan, Xiaohui

AU - Strauss, Michael A.

AU - Schneider, Donald P.

AU - Becker, Robert H.

AU - White, Richard L.

AU - Haiman, Zolt́an

AU - Gregg, Michael

AU - Pentericci, Laura

AU - Grebel, Eva K.

AU - Narayanan, Vijay K.

AU - Loh, Yeong Shang

AU - Richards, Gordon T.

AU - Gunn, James E.

AU - Lupton, Robert H.

AU - Knapp, Gillian R.

AU - Ivezić, Željko

AU - Brandt, W. N.

AU - Collinge, Matthew

AU - Hao, Lei

AU - Harbeck, Daniel

AU - Prada, Francisco

AU - Schaye, Joop

AU - Strateva, Iskra

AU - Zakamska, Nadia

AU - Anderson, Scott

AU - Brinkmann, Jon

AU - Bahcall, Neta A.

AU - Lamb, Don Q.

AU - Okamura, Sadanori

AU - Szalay, Alex

AU - York, Donald G.

PY - 2003/4

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N2 - We present the discovery of three new quasars at z > 6 in ∼ 1300 deg2 of Sloan Digital Sky Survey 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 Lyα 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 Lyα strength more typical of lower redshift quasars. Based on a sample of six quasars at z > 5.7 that cover 2870 deg2 presented in this paper and in Paper I, we estimate the comoving density of luminous quasars at z ∼ 6 and M1450 < -26.8 to be (8 ± 3) × 10-10 Mpc-3 (for H 0 = 50 km s-1 Mpc-1, Ω = 1). Hubble Space Telescope 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-redshift quasar sample suggests the bright-end slope of the quasar luminosity function at z ∼ 6 is shallower than ψ ∝ L-3.5 (2 σ), consistent with the absence of strongly lensed objects.

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KW - Quasars: emission lines quasars: general

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