Modelling of the Complex CASSOWARY/SLUGS Gravitational Lenses

Abstract

We present the first high-resolution images of CSWA 31, a gravitational lens system observed as part of the SLUGS (Sloan Lenses Unravelled by Gemini Studies) program. These systems exhibit complex image structure with the potential to strongly constrain the mass distribution of the massive lens galaxies, as well as the complex morphology of the sources. In this paper, we describe the strategy used to reconstruct the unlensed source profile and the lens galaxy mass profiles. We introduce a prior distribution over multi-wavelength sources that is realistic as a representation of our knowledge about the surface brightness profiles of galaxies and groups of galaxies. To carry out the inference computationally, we use Diffusive Nested Sampling, an efficient variant of Nested Sampling that uses Markov Chain Monte Carlo (MCMC) to sample the complex posterior distributions and compute the normalising constant. We demonstrate the efficacy of this approach with the reconstruction of the group-group gravitational lens system CSWA 31, finding the source to be composed of five merging spiral galaxies magnified by a factor of 13.

Accepted for publication in MNRAS

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Cited by in corpus (13)

• The CASSOWARY spectroscopy survey: A new sample of gravitationally lensed galaxies in SDSS
• A Keck Survey of Gravitationally-Lensed Star-Forming Galaxies: High Spatial Resolution Studies of Kinematics and Metallicity Gradients
• The Mass of the Black Hole in Arp 151 from Bayesian Modeling of Reverberation Mapping Data
• Data-Driven Reconstruction of Gravitationally Lensed Galaxies using Recurrent Inference Machines
• The SWELLS survey. III. Disfavouring "heavy" initial mass functions for spiral lens galaxies
• Probabilistic Catalogs for Crowded Stellar Fields
• Differentiable Strong Lensing: Uniting Gravity and Neural Nets through Differentiable Probabilistic Programming
• Lensed: a code for the forward reconstruction of lenses and sources from strong lensing observations
• Core or cusps: The central dark matter profile of a redshift one strong lensing cluster with a bright central image
• Constraining the multi-scale dark-matter distribution in CASSOWARY 31 with strong gravitational lensing and stellar dynamics
• The SAMI Galaxy Survey: Bayesian Inference for Gas Disk Kinematics using a Hierarchical Gaussian Mixture Model
• Measuring the total and baryonic mass profiles of the very massive CASSOWARY 31 strong lens. A fossil system at z ~ 0.7?
• Global Optimization methods for Gravitational Lens Systems with Regularized Sources