Halo-model signatures from 380 000 Sloan Digital Sky Survey luminous red galaxies with photometric redshifts

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Halo-model signatures from 380 000 Sloan Digital Sky Survey luminous red galaxies with photometric redshifts

Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/47689

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Title: Halo-model signatures from 380 000 Sloan Digital Sky Survey luminous red galaxies with photometric redshifts
Author(s): Blake, Chris; Collister, Adrian; Lahav, Ofer
Abstract: We analyse the small-scale clustering in 'MegaZ-LRG', a large photometric redshift catalogue of luminous red galaxies extracted from the imaging data set of the Sloan Digital Sky Survey. MegaZ-LRG, presented in a companion paper, spans the redshift range 0.4 < z < 0.7 with an rms redshift error σz ≈ 0.03(1 + z), covering 5914 deg2 to map out a total cosmic volume 2.5 h-3 Gpc3. In this study we use 380 000 photometric redshifts to measure significant deviations from the canonical power-law fit to the angular correlation function in a series of narrow redshift slices, in which we construct volume-limited samples. These deviations are direct signatures of the manner in which these galaxies populate the underlying network of dark matter haloes. We cleanly delineate the separate contributions of the 'one-halo' and 'two-halo' clustering terms and fit our measurements by parametrizing the halo occupation distribution N(M) of the galaxies. Our results are successfully fitted by a 'central' galaxy contribution with a 'soft' transition from zero to one galaxy, combined with a power-law 'satellite' galaxy component, the slope of which is a strong function of galaxy luminosity. The large majority of galaxies are classified as central objects of their host dark matter haloes rather than satellites in more massive systems. The effective halo mass of MegaZ-LRG galaxies lies in the range log 10(Meff/h-1 M⊙) = 13.61-13.80 (increasing with redshift assuming large-scale normalization σ8 = 0.8) for corresponding number densities in the range ng = 5.03 - 0.56 × 104 h-3 Mpc-3. Our results confirm the usefulness of the halo model for gaining physical insight into the patterns of galaxy clustering.
Publication type: Journal article
Research centre: Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing
Source: Monthly Notices of the Royal Astronomical Society, Vol. 385, no. 3 (Apr 2008), pp. 1257-1269
Publication year: 2008
FOR Code(s): 0201 Astronomical and Space Sciences; 020103 Cosmology and Extragalactic Astronomy
Keyword(s): Haloes; Galaxies; Large-scale structure; Universe
Publisher: Wiley-Blackwell Publishing
ISSN: 0035-8711
Publisher URL: http://dx.doi.org/10.1111/j.1365-2966.2007.11925.x
Peer reviewed