The impact of lens galaxy environments on the image separation distribution

Masamune Oguri, Charles R. Keeton, Neal Dalal

Research output: Contribution to journalArticlepeer-review

Abstract

We study the impact of lens galaxy environments on the image separation distribution of lensed quasars. We account for both environmental convergence and shear, using a joint distribution derived from galaxy formation models calibrated by galaxy-galaxy lensing data and number counts of massive elliptical galaxies. We find that the external field enhances lensing probabilities, particularly, at large image separations; the increase is ∼30 per cent at 9 = 3 arcsec and ∼200 per cent at θ = 5 arcsec, when we adopt a power-law source luminosity function Φ(L) ∝ L -2.1. The enhancement is mainly driven by convergence, which boosts both the image separation and magnification bias (for a fixed lens galaxy mass). These effects have been neglected in previous studies of lens statistics. Turning the problem around, we derive the posterior convergence and shear distributions and point out that they are strong functions of image separation; lens systems with larger image separations are more likely to lie in dense environments.

Original languageEnglish (US)
Pages (from-to)1451-1458
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume364
Issue number4
DOIs
StatePublished - Dec 21 2005

Keywords

  • Cosmology: theory
  • Dark matter
  • Gravitational lensing

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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