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The angular correlation function and hierarchical moments of  70 000 faint galaxies to R=23.5

Roche, N. and Eales, Stephen Anthony 1999. The angular correlation function and hierarchical moments of  70 000 faint galaxies to R=23.5. Monthly Notices of the Royal Astronomical Society 307 (3) , pp. 703-721. 10.1046/j.1365-8711.1999.02652.x

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We investigate the angular correlation function, ω(θ), and third- and fourth-order hierarchical moments of a large sample of ∼70 000 galaxies with apparent magnitudes 18.5≤R≤23.5. The data consist of 47 red-band INT Wide Field Camera CCD images, forming two widely separated fields of total areas 1.01 and 0.74 deg2. Galaxy clustering is detected with a high significance of ∼10s. Over the R=21 to 23.5 range of magnitude limits, the angular correlation functions approximately follow θ−0.8 power laws at θ>5 arcsec, with amplitudes consistent with previous surveys and best fitted by a luminosity evolution model in which galaxy clustering is approximately stable in proper coordinates (ɛ=0). Assuming the redshift distribution from our pure luminosity evolution (PLE) model and the present-day galaxy correlation radii from Loveday et al., we estimate the clustering evolution as Graphic for both fields combined, or Graphic for the larger of the two fields which is thought to be the better in data quality. On the larger of our fields, ω(θ) at 2≤θ≤5 significantly exceeds a ω(θ)∝θ−0.8 power law of the amplitude measured at θ>5 arcsec. If this excess of close pairs is due to interacting and merging galaxies, we estimate that it is consistent with the local fraction of galaxies in close (<19 h−1 kpc) pairs combined with a merger/interaction rate evolving as (1+z)m with Graphic. We derive the hierarchical moments s3(θ) and s4(θ) from the counts-in-cells of the 18.5≤R≤23.5 galaxies. We find relatively steep slopes of approximately θ−0.4 for s3(θ) and θ−0.6 for s4(θ), similar to those of the hierarchical moments of 17≤B≤20 galaxies in the EDSGCS at comparable physical scales. The s3(θ) and s4(θ) of the 18.5≤R≤23.5 galaxies show only a small reduction in normalization relative to those of the less deep EDSGCS survey, consistent with the expectations from N-body simulations of the evolving mass distribution. This indicates there is little change in the mean linear or non-linear biasing of galaxies from z∼0 to ∼1, and hence appears to favour luminosity evolution for galaxies over ‘transient starburst dwarf’ models, and supports the interpretation of the stable galaxy clustering as evidence for a low-ω universe.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QB Astronomy
Uncontrolled Keywords: surveys; galaxies: clusters; galaxies: evolution; large-scale structure of Universe
Publisher: Oxford Journals
ISSN: 0035-8711
Last Modified: 04 Jun 2017 04:59

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