### Abstract

We present constraints on the evolution of large-scale structure from a catalog of 710,000 galaxies with I_{AB} ≤ 24 derived from a KPNO 4 m CCD imaging survey of a contiguous 4° × 4° region. The advantage of using large contiguous surveys for measuring clustering properties on even modest angular scales is substantial: the effects of cosmic scatter are strongly suppressed. We provide highly accurate measurements of the two-point angular correlation function, ω(θ), as a function of magnitude on scales up to 1°.5. The amplitude of ω(θ) declines by a factor of ∼10 over the range 16 ≤ I ≤ 20 but only by a factor of 2-3 over the range 20 <I ≤ 23. For a redshift dependence of the spatial correlation function, ζ(r), parameterized as ζ(r, z) = (r/r_{0})^{-γ}(1 + z)^{-(3+ε)}, we find r_{0} = 5.2 ±0.4 h^{-1} Mpc, and ε ≳ 0 for I ≤ 20. This is in good agreement with the results from local redshift surveys. At I > 20, our best-fit values shift toward lower r_{0} and more negative ε. A strong covariance between r_{0} and ε prevents us from rejecting εe > 0 even at faint magnitudes, but if ε > 1, we strongly reject r_{0} ≲ 4 h^{-l} Mpc (comoving). The above expression for ζ(r, z) and our data give a correlation length of r_{0}(z = 0.5) ≈ 3.0 ± 0.4 h^{-1} Mpc, about a factor of 2 larger than the correlation length at z = 0.5 derived from the Canada-France Redshift Survey (CFRS). The small volume sampled by the CFRS and other deep redshift probes, however, makes these spatial surveys strongly susceptible to cosmic scatter and will tend to bias their derived correlation lengths toward the low end. Our results are consistent with redshift distributions in which ∼30%-50% of the galaxies at I = 23 lie at z > 1. The best-fit power-law slope of the correlation function remains independent of / magnitude for I <22. At fainter limits, there is a suggestive trend toward flatter slopes that occurs at fluxes consistent with similar trends seen by Neuschafier & Windhorst and Campos and coworkers. The galaxy counts span 11 magnitudes and provide an accurate calibration of the galaxy surface density. We find evidence for mild galaxy evolution: about 1 mag of brightening or a doubling of the density by I = 23 relative to an Ω_{0} = 1 no-evolution model, about 0.5 mag of brightening or a factor of 1.5 increase in surface density relative to an open model. Our galaxy counts agree well with those from the Hubble Deep Field survey and, thus, argue against a significant inclusion of subgalactic components in the latter census for I <24.

Original language | English |
---|---|

Pages (from-to) | 33-44 |

Number of pages | 12 |

Journal | Astrophysical Journal |

Volume | 506 |

Issue number | 1 PART I |

DOIs | |

Publication status | Published - 1998 |

### Fingerprint

### Keywords

- Galaxies: clusters: general
- Galaxies: statistics
- Large-scale structure of universe surveys

### ASJC Scopus subject areas

- Nuclear and High Energy Physics
- Space and Planetary Science

### Cite this

*Astrophysical Journal*,

*506*(1 PART I), 33-44. https://doi.org/10.1086/306245

**Clustering at high redshift : Precise constraints from a deep, wide-area survey.** / Postman, Marc; Lauer, Tod R.; Szapudi, I.; Oegerle, William.

Research output: Contribution to journal › Article

*Astrophysical Journal*, vol. 506, no. 1 PART I, pp. 33-44. https://doi.org/10.1086/306245

}

TY - JOUR

T1 - Clustering at high redshift

T2 - Precise constraints from a deep, wide-area survey

AU - Postman, Marc

AU - Lauer, Tod R.

AU - Szapudi, I.

AU - Oegerle, William

PY - 1998

Y1 - 1998

N2 - We present constraints on the evolution of large-scale structure from a catalog of 710,000 galaxies with IAB ≤ 24 derived from a KPNO 4 m CCD imaging survey of a contiguous 4° × 4° region. The advantage of using large contiguous surveys for measuring clustering properties on even modest angular scales is substantial: the effects of cosmic scatter are strongly suppressed. We provide highly accurate measurements of the two-point angular correlation function, ω(θ), as a function of magnitude on scales up to 1°.5. The amplitude of ω(θ) declines by a factor of ∼10 over the range 16 ≤ I ≤ 20 but only by a factor of 2-3 over the range 20 <I ≤ 23. For a redshift dependence of the spatial correlation function, ζ(r), parameterized as ζ(r, z) = (r/r0)-γ(1 + z)-(3+ε), we find r0 = 5.2 ±0.4 h-1 Mpc, and ε ≳ 0 for I ≤ 20. This is in good agreement with the results from local redshift surveys. At I > 20, our best-fit values shift toward lower r0 and more negative ε. A strong covariance between r0 and ε prevents us from rejecting εe > 0 even at faint magnitudes, but if ε > 1, we strongly reject r0 ≲ 4 h-l Mpc (comoving). The above expression for ζ(r, z) and our data give a correlation length of r0(z = 0.5) ≈ 3.0 ± 0.4 h-1 Mpc, about a factor of 2 larger than the correlation length at z = 0.5 derived from the Canada-France Redshift Survey (CFRS). The small volume sampled by the CFRS and other deep redshift probes, however, makes these spatial surveys strongly susceptible to cosmic scatter and will tend to bias their derived correlation lengths toward the low end. Our results are consistent with redshift distributions in which ∼30%-50% of the galaxies at I = 23 lie at z > 1. The best-fit power-law slope of the correlation function remains independent of / magnitude for I <22. At fainter limits, there is a suggestive trend toward flatter slopes that occurs at fluxes consistent with similar trends seen by Neuschafier & Windhorst and Campos and coworkers. The galaxy counts span 11 magnitudes and provide an accurate calibration of the galaxy surface density. We find evidence for mild galaxy evolution: about 1 mag of brightening or a doubling of the density by I = 23 relative to an Ω0 = 1 no-evolution model, about 0.5 mag of brightening or a factor of 1.5 increase in surface density relative to an open model. Our galaxy counts agree well with those from the Hubble Deep Field survey and, thus, argue against a significant inclusion of subgalactic components in the latter census for I <24.

AB - We present constraints on the evolution of large-scale structure from a catalog of 710,000 galaxies with IAB ≤ 24 derived from a KPNO 4 m CCD imaging survey of a contiguous 4° × 4° region. The advantage of using large contiguous surveys for measuring clustering properties on even modest angular scales is substantial: the effects of cosmic scatter are strongly suppressed. We provide highly accurate measurements of the two-point angular correlation function, ω(θ), as a function of magnitude on scales up to 1°.5. The amplitude of ω(θ) declines by a factor of ∼10 over the range 16 ≤ I ≤ 20 but only by a factor of 2-3 over the range 20 <I ≤ 23. For a redshift dependence of the spatial correlation function, ζ(r), parameterized as ζ(r, z) = (r/r0)-γ(1 + z)-(3+ε), we find r0 = 5.2 ±0.4 h-1 Mpc, and ε ≳ 0 for I ≤ 20. This is in good agreement with the results from local redshift surveys. At I > 20, our best-fit values shift toward lower r0 and more negative ε. A strong covariance between r0 and ε prevents us from rejecting εe > 0 even at faint magnitudes, but if ε > 1, we strongly reject r0 ≲ 4 h-l Mpc (comoving). The above expression for ζ(r, z) and our data give a correlation length of r0(z = 0.5) ≈ 3.0 ± 0.4 h-1 Mpc, about a factor of 2 larger than the correlation length at z = 0.5 derived from the Canada-France Redshift Survey (CFRS). The small volume sampled by the CFRS and other deep redshift probes, however, makes these spatial surveys strongly susceptible to cosmic scatter and will tend to bias their derived correlation lengths toward the low end. Our results are consistent with redshift distributions in which ∼30%-50% of the galaxies at I = 23 lie at z > 1. The best-fit power-law slope of the correlation function remains independent of / magnitude for I <22. At fainter limits, there is a suggestive trend toward flatter slopes that occurs at fluxes consistent with similar trends seen by Neuschafier & Windhorst and Campos and coworkers. The galaxy counts span 11 magnitudes and provide an accurate calibration of the galaxy surface density. We find evidence for mild galaxy evolution: about 1 mag of brightening or a doubling of the density by I = 23 relative to an Ω0 = 1 no-evolution model, about 0.5 mag of brightening or a factor of 1.5 increase in surface density relative to an open model. Our galaxy counts agree well with those from the Hubble Deep Field survey and, thus, argue against a significant inclusion of subgalactic components in the latter census for I <24.

KW - Galaxies: clusters: general

KW - Galaxies: statistics

KW - Large-scale structure of universe surveys

UR - http://www.scopus.com/inward/record.url?scp=22444455765&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=22444455765&partnerID=8YFLogxK

U2 - 10.1086/306245

DO - 10.1086/306245

M3 - Article

VL - 506

SP - 33

EP - 44

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART I

ER -