A strong-lens survey in AEGIS: the influence of large-scale structure

Leonidas A. Moustakas*, Phil Marshall, Jeffrey A. Newman, Alison L. Coil, Michael C. Cooper, Marc Davis, Christopher D. Fassnacht, Puragra Guhathakurta, Andrew Hopkins, Anton Koekemoer, Nicholas P. Konidaris, Jennifer M. Lotz, Christopher N A Willmer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


We report on a visual search for galaxy-scale strong gravitational lenses over 650 arcmin2 of HST ACS (V606 and I814) imaging in the DEEP2 Extended Groth Strip. This field has Keck DEIMOS spectroscopy of ∼ 14,000 galaxies (∼ 75% complete to RAB < 24.1). We identify three strong galaxy-galaxy lenses: HST J141735+522646 is a previously known four-image lens (the "Cross"; zl, = 0.8106, zs = 3.40); HST J141820+523611 (the "Dewdrop"; zl = 0.5798, zs = 0.9818) features two pairs of arcs; and HST J141833+524352 (the "Anchor"; zl = 0.4625, no z s,) has one pair of arcs. Based on a normalized local density (1 + δ3), lenses are found to be in both under- and overdense local environments. All three lenses are fit well by singular isothermal ellipsoid models including external shear, with Xv 2 ∼ 1. The model shears are ∼ 10%. Approximating all line-of-sight galaxies as singular isothermal sphere halos truncated at 200 h-1 kpc, with masses estimated through the Faber-Jackson relation, infers shears of ∼ 2%, much smaller than those required by the models. Therefore, the corresponding convergence estimates must also be suspect. If more realistic treatment of galaxies (and the large-scale structure that they are embedded in) were to match the inferred shears to the model shears, then the true convergence could be measured and the mass-sheet degeneracy broken.

Original languageEnglish
Pages (from-to)L31-L34
Number of pages4
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 1 May 2007
Externally publishedYes


  • Galaxies: high-redshift
  • Gravitational lensing
  • Large-scale structure of universe


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