The redshift-space two-point correlation function of ELAIS-S1 galaxies |
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| Authors: | V D'Elia E Branchini F La Franca V Baccetti I Matute F Pozzi C Gruppioni |
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| Institution: | INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio-Catone (RM), Italy;Dipartimento di Fisica, Universitàdegli Studi 'Roma Tre', Via della Vasca Navale 84, I-00146 Roma, Italy;Max-Planck-Institut für extraterrestrische Physik (MPE), Giessenbachstrasse, Postfach 1312, 85741 Garching, Germany;Dipartimento di Astronomia, Universitàdi Bologna, viale Berti Pichat 6, I-40127 Bologna, Italy;INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy |
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| Abstract: | We investigate the clustering properties of galaxies in the recently completed ELAIS-S1 redshift survey through their spatial two-point autocorrelation function. We used a subsample of the ELAIS-S1 catalogue covering approximately 4 deg2 and consisting of 148 objects selected at 15 μm with a flux >0.5 mJy and a redshift z < 0.5 . We detected a positive signal in the correlation function that in the range of separations 1–10 h ?1 Mpc is well approximated by a power law with a slope γ= 1.4 ± 0.25 and a correlation length s 0= 5.4 ± 1.2 h ?1 Mpc , at the 90 per cent significance level. This result is in good agreement with the redshift-space correlation function measured in more local samples of mid-infrared-selected galaxies such as the IRAS Point Source Catalog (PSC z ) redshift survey. This suggests a lack of significant clustering evolution of infrared-selected objects out to z = 0.5 that is further confirmed by the consistency found between the correlation functions measured in a local ( z < 0.2) and a distant (0.2 < z < 0.5) subsample of ELAIS-S1 galaxies. We also confirm that optically selected galaxies in the local redshift surveys, especially those of the SDSS sample, are significantly more clustered than infrared objects. |
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| Keywords: | galaxies: clusters: general galaxies: evolution cosmology: observations large-scale structure of Universe infrared: galaxies |
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