### Abstract

We report on the first result from the clustering analysis of SDSS quasars. We computed the two-point correlation function (2PCF) of SDSS quasars in redshift space at 8 h ^{-1} Mpc < s < 500 h ^{-1} Mpc, with particular attention to its baryonic signature. Our sample consisted of 19986 quasars extracted from the SDSS Data Release 4. The redshift range of the sample is 0.72 ≤ z ≤ 2.24 (the mean redshift is z̄ = 1.46) and the reddening-corrected i-band apparent magnitude range is 15.0 ≤ m _{i.rc} ≤ 19.1. Due to the relatively low number density of the quasar sample, the bump in the power spectrum due to the baryon density, Ω _{b}, is not clearly visible. The effect of the baryon density is, however, to distort the overall shape of the 2PCF. The degree of distortion makes it an interesting alternate measure of the baryonic signature. Assuming a scale-independent linear bias and a spatially flat universe, we combined the observed quasar 2PCF and the predicted matter 2PCF to put constraints on Ω _{b} and Ω _{Λ} (the cosmological constant). Our result was fitted as 0.80 -2.8Ω _{b} < Ω _{Λ} < 0.90 - 1.4Ω _{b} at the 2σ confidence level. The "mean" bias parameter of our quasar sample is 1.59 σ _{8} ^{-1} (for Ω _{b} = 0.04 and Ω _{Λ} = 0.7), where σ _{8} is the top-hat mass fluctuation amplitude at 8 h ^{-1} Mpc. We also estimated the corresponding bias parameter of quasars at z = 0, b _{QSO.Fry}(0), assuming Fry's bias evolution model. For Ω _{b} = 0.04, Ω _{Λ} = 0.73, and Ω _{d} = 0.23, we found b _{QSO.Fry}(0) = 0.54 + 0.83 σ _{8} ^{-1} which is valid for 0.6 < σ _{8} < 1.0.

Original language | English (US) |
---|---|

Pages (from-to) | 529-540 |

Number of pages | 12 |

Journal | Publications of the Astronomical Society of Japan |

Volume | 57 |

Issue number | 4 |

State | Published - 2005 |

### Fingerprint

### Keywords

- Cosmology: large-scale structure of universe
- Cosmology: observations
- Galaxies: quasars: general
- Methods: statistical

### ASJC Scopus subject areas

- Astronomy and Astrophysics
- Space and Planetary Science

### Cite this

*Publications of the Astronomical Society of Japan*,

*57*(4), 529-540.

**Large-scale clustering of sloan digital sky survey quasars : Impact of the baryon density and the cosmological constant.** / Yahata, Kazuhiro; Suto, Yasushi; Kayo, Issha; Matsubara, Takahiko; Connolly, Andrew J.; Berk, Daniel Vanden; Sheth, Ravi; Szapudi, István; Anderson, Scott F.; Bahcall, Neta; Brinkmann, Jon; Csabai, István; Fan, Xiaohui; Loveday, Jon; Szalay, Alexander S.; York, Donald.

Research output: Contribution to journal › Article

*Publications of the Astronomical Society of Japan*, vol. 57, no. 4, pp. 529-540.

}

TY - JOUR

T1 - Large-scale clustering of sloan digital sky survey quasars

T2 - Impact of the baryon density and the cosmological constant

AU - Yahata, Kazuhiro

AU - Suto, Yasushi

AU - Kayo, Issha

AU - Matsubara, Takahiko

AU - Connolly, Andrew J.

AU - Berk, Daniel Vanden

AU - Sheth, Ravi

AU - Szapudi, István

AU - Anderson, Scott F.

AU - Bahcall, Neta

AU - Brinkmann, Jon

AU - Csabai, István

AU - Fan, Xiaohui

AU - Loveday, Jon

AU - Szalay, Alexander S.

AU - York, Donald

PY - 2005

Y1 - 2005

N2 - We report on the first result from the clustering analysis of SDSS quasars. We computed the two-point correlation function (2PCF) of SDSS quasars in redshift space at 8 h -1 Mpc < s < 500 h -1 Mpc, with particular attention to its baryonic signature. Our sample consisted of 19986 quasars extracted from the SDSS Data Release 4. The redshift range of the sample is 0.72 ≤ z ≤ 2.24 (the mean redshift is z̄ = 1.46) and the reddening-corrected i-band apparent magnitude range is 15.0 ≤ m i.rc ≤ 19.1. Due to the relatively low number density of the quasar sample, the bump in the power spectrum due to the baryon density, Ω b, is not clearly visible. The effect of the baryon density is, however, to distort the overall shape of the 2PCF. The degree of distortion makes it an interesting alternate measure of the baryonic signature. Assuming a scale-independent linear bias and a spatially flat universe, we combined the observed quasar 2PCF and the predicted matter 2PCF to put constraints on Ω b and Ω Λ (the cosmological constant). Our result was fitted as 0.80 -2.8Ω b < Ω Λ < 0.90 - 1.4Ω b at the 2σ confidence level. The "mean" bias parameter of our quasar sample is 1.59 σ 8 -1 (for Ω b = 0.04 and Ω Λ = 0.7), where σ 8 is the top-hat mass fluctuation amplitude at 8 h -1 Mpc. We also estimated the corresponding bias parameter of quasars at z = 0, b QSO.Fry(0), assuming Fry's bias evolution model. For Ω b = 0.04, Ω Λ = 0.73, and Ω d = 0.23, we found b QSO.Fry(0) = 0.54 + 0.83 σ 8 -1 which is valid for 0.6 < σ 8 < 1.0.

AB - We report on the first result from the clustering analysis of SDSS quasars. We computed the two-point correlation function (2PCF) of SDSS quasars in redshift space at 8 h -1 Mpc < s < 500 h -1 Mpc, with particular attention to its baryonic signature. Our sample consisted of 19986 quasars extracted from the SDSS Data Release 4. The redshift range of the sample is 0.72 ≤ z ≤ 2.24 (the mean redshift is z̄ = 1.46) and the reddening-corrected i-band apparent magnitude range is 15.0 ≤ m i.rc ≤ 19.1. Due to the relatively low number density of the quasar sample, the bump in the power spectrum due to the baryon density, Ω b, is not clearly visible. The effect of the baryon density is, however, to distort the overall shape of the 2PCF. The degree of distortion makes it an interesting alternate measure of the baryonic signature. Assuming a scale-independent linear bias and a spatially flat universe, we combined the observed quasar 2PCF and the predicted matter 2PCF to put constraints on Ω b and Ω Λ (the cosmological constant). Our result was fitted as 0.80 -2.8Ω b < Ω Λ < 0.90 - 1.4Ω b at the 2σ confidence level. The "mean" bias parameter of our quasar sample is 1.59 σ 8 -1 (for Ω b = 0.04 and Ω Λ = 0.7), where σ 8 is the top-hat mass fluctuation amplitude at 8 h -1 Mpc. We also estimated the corresponding bias parameter of quasars at z = 0, b QSO.Fry(0), assuming Fry's bias evolution model. For Ω b = 0.04, Ω Λ = 0.73, and Ω d = 0.23, we found b QSO.Fry(0) = 0.54 + 0.83 σ 8 -1 which is valid for 0.6 < σ 8 < 1.0.

KW - Cosmology: large-scale structure of universe

KW - Cosmology: observations

KW - Galaxies: quasars: general

KW - Methods: statistical

UR - http://www.scopus.com/inward/record.url?scp=25144496105&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=25144496105&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:25144496105

VL - 57

SP - 529

EP - 540

JO - Publication of the Astronomical Society of Japan

JF - Publication of the Astronomical Society of Japan

SN - 0004-6264

IS - 4

ER -