AutoLens: automated modeling of a strong lens’s light, mass, and source

J W Nightingale,S Dye,Richard J Massey

doi:10.1093/mnras/sty1264

J W Nightingale, S Dye + Show 1 more

Open Access

https://doi.org/10.1093/mnras/sty1264

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Abstract

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.

Highlights

Strong gravitational lensing offers a unique means of measuring the mass distribution and composition of galaxies within our Universe
The results presented in this work use only the MultiNest samples generated from the second phase of the main pipeline unless stated otherwise
The Navarro– Frenk–White (NFW) model is summarized with its normalization κd and axis-ratio qd whereas a light profile’s mass component uses instead its mass-to-light ratio l

Summary

Introduction

Strong gravitational lensing offers a unique means of measuring the mass distribution and composition of galaxies within our Universe. 2009, 2011), and cosmology (Suyu et al 2013; Collett & Auger 2014; Suyu et al 2016; Wong et al 2017). This analysis provides a full reconstruction of the highly magnified source galaxy and offers an unprecedented view of the high redshift Universe (Shirazi et al 2014; Dye et al 2014, 2015; Rybak et al 2015; Swinbank et al 2015). Measuring MEin requires relatively simple lens modeling methodology (e.g. Bolton et al 2008; Sonnenfeld et al 2013a) and has already been performed on the majority of known strong lenses over the past decade (Bolton et al 2008; Koopmans et al 2009; Bolton et al 2012; Brewer et al 2012; Dutton et al 2013; Sonnenfeld et al 2013b, 2015)

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