Journal Article

Strong-lensing analysis of MS 1358.4+6245: New multiple images and implications for the well-resolved <i>z</i>= 4.92 galaxy

Adi Zitrin, Tom Broadhurst, Dan Coe, Jori Liesenborgs, Narciso Benítez, Yoel Rephaeli, Holland Ford and Keiichi Umetsu

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 413, issue 3, pages 1753-1763
Published in print May 2011 | ISSN: 0035-8711
Published online May 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2011.18252.x
Strong-lensing analysis of MS 1358.4+6245: New multiple images and implications for the well-resolved z= 4.92 galaxy

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We present a strong-lensing analysis of the galaxy cluster MS 1358.4+6245 (z= 0.33), in deep six-band HST/ACS imaging. In addition to the well-studied system at z= 4.92, our modelling method uncovers 19 new multiply lensed images belonging to seven background sources, so that a total of 23 images and their redshifts are used to accurately constrain the inner mass distribution. We derive a relatively shallow inner mass profile, d log Σ/d log r≃−0.33 ± 0.05 (r < 200 kpc), with a much higher magnification than estimated previously by models constrained only by the z= 4.92 system. Using these many new images we can apply a non-parametric adaptive-grid method, which also yields a shallow mass profile without prior assumptions, strengthening our conclusions. The total magnification of the zs= 4.92 galaxy is high, about a ∼100 times over its four images, so that the inferred source size, luminosity and star formation rate are about ∼5 times smaller than previous estimates, corresponding to a dwarf-sized galaxy of radius ≃1 kpc. A detailed image of the interior morphology of the source is generated with a high effective resolution of only ≃50 pc, thanks to the high magnification and to the declining angular diameter distance above z∼ 1.5 for the standard cosmology, so that this image apparently represents the best resolved object known at high redshift.

Keywords: gravitational lensing: strong; galaxies: clusters: general; galaxies: clusters: individual: MS 1358.4+6245; galaxies: high-redshift; dark matter

Journal Article.  7920 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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