Angular cross-correlation of galaxies: a probe of gravitational lensing by large-scale structure |
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Authors: | Moessner,& Bhuvnesh Jain |
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Affiliation: | Max Planck Institut für Astrophysik, Karl-Schwarzschild-Straße 1, 85740 Garching, Germany,;Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA |
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Abstract: | The angular cross-correlation between two galaxy samples separated in redshift is shown to be a useful measure of weak lensing by large-scale structure. Angular correlations in faint galaxies arise as a result of spatial clustering of the galaxies as well as gravitational lensing by dark matter along the line of sight. The lensing contribution to the two-point autocorrelation function is typically small compared with the gravitational clustering. However, the cross-correlation between two galaxy samples is almost unaffected by gravitational clustering provided that their redshift distributions do not overlap. The cross-correlation is then induced by magnification bias resulting from lensing by large-scale structure. We compute the expected amplitude of the cross-correlation for popular theoretical models of structure formation. For two populations with mean redshifts of ≃0.3 and 1, we find a cross-correlation signal of ≃1 per cent on arcmin scales and ≃3 per cent on scales of a few arcsec. The dependence on the cosmological parameters Ω and Λ, the dark matter power spectrum and the bias factor of the foreground galaxy population is explored. |
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Keywords: | galaxies: clusters: general cosmology: observations gravitational lensing large-scale structure of Universe. |
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