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Free keywords:
galaxies: clusters: general
galaxies: fundamental parameters
galaxies: high-redshift
gravitational lensing: strong
submillimeter:
galaxies
Astrophysics - Astrophysics of Galaxies
Abstract:
We present Hubble Space Telescope WFC3-IR imaging in the fields of six apparently bright dusty star-forming galaxies (DSFGs) at z = 2-4 identified by their rest-frame far-infrared colors using the Planck and Herschel space facilities. We detect near-infrared counterparts for all six submillimeter sources, allowing us to undertake strong-lensing analyses. One field in particular stands out for its prominent giant arcs, PLCK G165.7+67.0 (G165). After combining the color and morphological information, we identify 11 sets of image multiplicities in this one field. We construct a strong-lensing model constrained by this lensing evidence, which uncovers a bimodal spatial mass distribution, and from which we measure a mass of (2.6 ± 0.11) × 1014 M ☉ within ̃250 kpc. The bright (S 350 ≈ 750 mJy) DSFG appears as two images: a giant arc with a spatial extent of 4\buildrel{\prime\prime}\over{.} 5 that is merging with the critical curve, and a lower-magnification counterimage that is detected in our new longer-wavelength ground- and space-based imaging data. Using our ground-based spectroscopy, we calculate a dynamical mass of {1.3}-0.70+0.04× {10}15 M ☉ to the same fixed radius, although this value may be inflated relative to the true value if the velocity distribution is enhanced in the line-of-sight direction. We suggest that the bimodal mass taken in combination with the weak X-ray flux and low SZ decrement may be explained as a pre-merger for which the intracluster gas is diluted along the line of sight, while the integrated surface mass density is supercritical to strong-lensing effects.
