TY - JOUR
T1 - Strong-lensing analysis of MS 1358.4+6245
T2 - New multiple images and implications for the well-resolved z= 4.92 galaxy
AU - Zitrin, Adi
AU - Broadhurst, Tom
AU - Coe, Dan
AU - Liesenborgs, Jori
AU - Benítez, Narciso
AU - Rephaeli, Yoel
AU - Ford, Holland
AU - Umetsu, Keiichi
PY - 2011/5
Y1 - 2011/5
N2 - 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, dlogΣ/dlogr≃-0.33 ± 0.05 (r < 200kpc), 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 ≃1kpc. A detailed image of the interior morphology of the source is generated with a high effective resolution of only ≃50pc, 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.
AB - 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, dlogΣ/dlogr≃-0.33 ± 0.05 (r < 200kpc), 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 ≃1kpc. A detailed image of the interior morphology of the source is generated with a high effective resolution of only ≃50pc, 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.
KW - Dark matter
KW - Galaxies: clusters: general
KW - Galaxies: high-redshift
KW - Gravitational lensing: strong
UR - http://www.scopus.com/inward/record.url?scp=79955760041&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2966.2011.18252.x
DO - 10.1111/j.1365-2966.2011.18252.x
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AN - SCOPUS:79955760041
SN - 0035-8711
VL - 413
SP - 1753
EP - 1763
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -