We have modelled Atacama Large Millimeter/sub-millimeter Array (ALMA) long baseline imaging of the strong gravitational lens system H-ATLAS J090311.6+003906 (SDP.81). We have reconstructed the distribution of band 6 and 7 continuum emission in the z = 3.042 source and we have determined its kinematic properties by reconstructing CO(5-4) and CO(8-7) line emission in bands 4 and 6. The continuum imaging reveals a highly non-uniform distribution of dust with clumps on scales of ∼ 200 pc. In contrast, the CO line emission shows a relatively smooth, disk-like velocity field which is well fit by a rotating disk model with an inclination angle of (40 ± 5) • and an asymptotic rotation velocity of 320 kms −1 . The inferred dynamical mass within 1.5 kpc is (3.5 ± 0.5) × 10 10 M ⊙ which is comparable to the total molecular gas masses of (2.7 ± 0.5) × 10 10 M ⊙ and (3.5 ± 0.6) × 10 10 M ⊙ from the dust continuum emission and CO emission respectively. Our new reconstruction of the lensed HST near-infrared emission shows two objects which appear to be interacting, with the rotating disk of gas and dust revealed by ALMA distinctly offset from the near-infrared emission. The clumpy nature of the dust and a low value of the Toomre parameter of Q ∼ 0.3 suggest that the disk is in a state of collapse. We estimate a star formation rate in the disk of 470 ± 80 M ⊙ /yr with an efficiency ∼ 65 times greater than typical low-redshift galaxies. Our findings add to the growing body of evidence that the most infra-red luminous, dust obscured galaxies in the high redshift Universe represent a population of merger induced starbursts.

This work presents AutoLens, the first entirely automated modeling suite for the analysis of galaxy-scale strong gravitational lenses. AutoLens simultaneously models the lens galaxy's light and mass whilst reconstructing the extended source galaxy on an adaptive pixel-grid. The method's approach to source-plane discretization is amorphous, adapting its clustering and regularization to the intrinsic properties of the lensed source. The lens's light is fitted using a superposition of Sersic functions, allowing AutoLens to cleanly deblend its light from the source. Single component mass models representing the lens's total mass density profile are demonstrated, which in conjunction with light modeling can detect central images using a centrally cored profile. Decomposed mass modeling is also shown, which can fully decouple a lens's light and dark matter and determine whether the two component are geometrically aligned. The complexity of the light and mass models are automatically chosen via Bayesian model comparison. These steps form AutoLens's automated analysis pipeline, such that all results in this work are generated without any user-intervention. This is rigorously tested on a large suite of simulated images, assessing its performance on a broad range of lens profiles, source morphologies and lensing geometries. The method's performance is excellent, with accurate light, mass and source profiles inferred for data sets representative of both existing Hubble imaging and future Euclid wide-field observations.

We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 µm-bright candidate lensing systems identified by the Herschel Multi-tiered Extragalactic Survey (HerMES) and Herschel Astrophysical Terahertz Survey (H-ATLAS). Out of 87 candidates with near-IR imaging, 15 (∼ 17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and previous lensing models for sub-millimeter galaxies. For four new sources that also have high-resolution sub-mm maps, we test for differential lensing between the stellar and dust components and find that the 880 µm magnification factor (µ 880 ) is ∼ 1.5 times higher than the near-IR magnification factor (µ NIR ), on average. We also find that the stellar emission is ∼ 2 times more extended in size than dust. The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar. c AB mag 1HerMES S250 J002854.0-420457 HELAISS04 J = 62 × 4 J = 25.8 1HerMES S250 J002906.3-421420 HELAISS01 J = 62 × 4 J = 25.4 1HerMES S250 J003823.7-433705 HELAISS02 J = 125 × 4 J = 25.7 1HerMES S250 J021620.0-032520 HXMM26 Kp = 60 × 30 Kp = 25.6 e 1HerMES S250 J021632.1-053422 HXMM14 J = 125 × 4 J = 25.6 1HerMES S250 J021830.6-053125 HXMM02 J = 177 × 4, Kp = 60 × 18 J = 26.3, Kp = 25.6 e 1HerMES S250 J021836.7-035316 HXMM13 J = 62 × 4 J = 25.6 1HerMES S250 J021942.9-052433 HXMM20 J = 125 × 4 J = 25.6 1HerMES S250 J022016.6-060144 HXMM01 J = 62 × 4, Ks = 80 × 35 J = 25.5, Ks = 25.6 1HerMES S250 J022021.8-015329 HXMM04 J = 62 × 4 J = 25.6 1HerMES S250 J022029.2-064846 HXMM09 J = 62 × 4, H = 120 × 12, K = 80 × 15 J = 25.2, H = 24.8, K = 24.5 1HerMES S250 J022135.2-062618 HXMM03 J = 62 × 4 J = 25.4 1HerMES S250 J022201.7-033340 HXMM11 Ks = 100 × 18 Ks = 25.6 e 1HerMES S250 J022205.5-070727 HXMM23 J = 62 × 4 J = 25.2 1HerMES S250 J022212.9-070224 HXMM28 J = 125 × 4 J = 25.6 1HerMES S250 J022250.8-032414 HXMM22 J = 62 × 4 J = 25.4 1HerMES S250 J022515.3-024707 HXMM19 J = 62 × 4 J = 25.3 1HerMES S250 J022517.5-044610 HXMM27 J = 62 × 4 J = 25.6 1HerMES S250 J022547.9-041750 HXMM05 J = 62 × 4 J = 25.8 1HerMES S250 J023006.0-034153 HXMM12 J = 62 × 4 J = 25.2 1HerMES S250 J032434.4-292646 HECDFS08 J = 62 × 4 J = 25.4 1HerMES S250 J032443.1-282134 HECDFS03 J = 125 × 4 J = 25.4 1HerMES S250 J032636.4-270045 HECDFS05 J = 62 × 4 J = 25.6 1HerMES S250 J032712.7-285106 HECDFS09 J = 62 × 4 J = 25.5 1HerMES S250 J033118.0-272015 HECDFS11 J = 62 × 4 J = 25.3 1HerMES S250 J033210.8-270536 HECDFS04 J = 62 × 4 J = 26.0 1HerMES S250 J033732.5-295353 HECDFS02 J = 177 × 4 J = 26.8 1HerMES S250 J043340.5-540338 HADFS04 J = 62 × 4 J = 25.6 1HerMES S250 J043829.8-541832 HADFS02 J = 62 × 4 J = 25....

We have determined the mass-density radial profiles of the first five strong gravitational lens systems discovered by the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). We present an enhancement of the semi-linear lens inversion method of Warren & Dye which allows simultaneous reconstruction of several different wavebands and apply this to dual-band imaging of the lenses acquired with the Hubble Space Telescope. The five systems analysed here have lens redshifts which span a range, 0.22 z 0.94. Our findings are consistent with other studies by concluding that: 1) the logarithmic slope of the total mass density profile steepens with decreasing redshift; 2) the slope is positively correlated with the average total projected mass density of the lens contained within half the effective radius and negatively correlated with the effective radius; 3) the fraction of dark matter contained within half the effective radius increases with increasing effective radius and increases with redshift.