Strong lensing statistics in large, z~<0.2 surveys: bias in the lens galaxy population

dc.creatorMoeller, Ole
dc.creatorKitzbichler, Manfred
dc.creatorNatarajan, Priyamvada
dc.date2006-07-03
dc.date2006-07-28
dc.date.accessioned2026-07-07T11:04:04Z
dc.date.available2026-07-07T11:04:04Z
dc.descriptionWe calculate the expected lensing statistics of the galaxy population in large, low-redshift surveys. Galaxies are modeled using realistic, multiple components: a dark matter halo, a bulge component and disc. We use semi-analytic models of galaxies coupled with dark matter haloes in the Millennium Run to model the lens galaxy population. We predict that a fraction of 1.4+/-0.18*10^-3 of radio sources will be lensed by galaxies within a survey like the 2dF below z<0.2. With a simulated sample of lensed radio sources, the predicted lensing galaxy population consists mainly of ellipticals (~80%) with an average lens velocity dispersion of 164+/-3 km/s, producing typical image separations of ~3 arcsec. The lens galaxy population lies on the fundamental plane but its velocity dispersion distribution is shifted to higher values compared to all early-type galaxies. Taking magnification bias into account, we predict that the ratio of 4:2 image systems is 30+/-5%, consistent with the observed ratio found in the Cosmic Lens All-Sky Survey. We also find that the population of 4-image lens galaxies is distinguishable from the population of lens galaxies in 2-image systems. Our key result is the explicit demonstration that the population of lens galaxies differs markedly from the galaxy population as a whole: lens galaxies have a higher average luminosity and reside in more massive haloes than the overall sample of ellipticals. This bias restricts our ability to infer galaxy evolution parameters from a sample of lensing galaxies. (abridged)
dc.description13 pages, 13 figures, submitted to MNRAS. Removed double figure and added correct figure 9
dc.identifierhttps://arxiv.org/abs/astro-ph/0607032
dc.identifierhttp://arxiv.org/abs/astro-ph/0607032
dc.identifierMon.Not.Roy.Astron.Soc.379:1195-1208,2007
dc.identifierdoi:10.1111/j.1365-2966.2007.12004.x
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/188762
dc.subjectAstrophysics
dc.titleStrong lensing statistics in large, z~<0.2 surveys: bias in the lens galaxy population
dc.typetext

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