Strong-lensing analysis of A2744 with MUSE and Hubble Frontier Fields images

Abstract

We present an analysis of MUSE observations obtained on the massive Frontier Fields cluster Abell 2744. This new dataset covers the entire multiply-imaged region around the cluster core. The combined catalog consists of 514 spectroscopic redshifts (with 414 new identifications). We use this redshift information to perform a strong-lensing analysis revising multiple images previously found in the deep Frontier Field images, and add three new MUSE-detected multiply-imaged systems with no obvious HST counterpart. The combined strong lensing constraints include a total of 60 systems producing 188 images altogether, out of which 29 systems and 83 images are spectroscopically confirmed, making Abell 2744 one of the most well-constrained clusters to date. Thanks to the large amount of spectroscopic redshifts we model the influence of substructures at larger radii, using a parametrisation including two cluster-scale components in the cluster core and several group-scale in the outskirts. The resulting model accurately reproduces all the spectroscopic multiple systems, reaching an rms of 0.67 in the image plane. The large number of MUSE spectroscopic redshifts gives us a robust model, which we estimate reduces the systematic uncertainty on the 2D mass distribution by up to ∼ 2.5 times the statistical uncertainty in the cluster core. In addition, from a combination of the parametrisation and the set of constraints, we estimate the relative systematic uncertainty to be up to 9% at 200kpc.

Spectral variations of Lyman $\alpha$ emission within strongly lensed sources observed with MUSE

“…We present here in more details the two lens models used in our analysis. The procedure described uses the Lenstool software and is similar to previous cluster mass models from our team (Richard et al 2010b;Jauzac et al 2016;Mahler et al 2018). We used the sky positions and redshifts of multiple images to constrain a parametric mass model of each cluster.…”

hybrid-lenstool: a self-consistent algorithm to model galaxy clusters with strong- and weak-lensing simultaneously

“…• a catalogue of 246 galaxy-scale potentials, with parameters r * cut = 14 kpc, r * core = 0.15 kpc and σ * 0 = 155 km/s. We note that positions and shapes of these potentials correspond to the true galaxy distribution in Abell 2744 as measured in Mahler et al (2018), and covers only the core region of the simulated cluster.…”

“…Indeed, gravitational lensing is a unique tool to map the mass distribution of the lenses as it is independent of their dynamical state, thereby providing crucial in-situ information on the physics of these objects. In the case of cluster lenses, a lot of work has been done from gravitational lensing mass maps and multi-wavelength analyses to constrain cluster physics (e.g., Kneib et al 2003;Clowe, Gonzalez & Markevitch 2004;Bradač et al 2006;Merten et al 2011;Diego et al 2015;Eckert et al 2015;Jauzac et al 2012Jauzac et al , 2015Mahler et al 2018;Sharon et al 2015Sharon et al , 2019, and dark matter properties (e.g., Natarajan et al , 2017Bradač et al 2008;Harvey et al 2015;Harvey, Kneib & Jauzac 2016;Harvey et al 2017Harvey et al , 2019Massey et al 2015Massey et al , 2018Jauzac et al 2016aJauzac et al , 2018. Moreover, lensing can give us hints on galaxy evolution (e.g.…”

Exploring effects on magnifications due to line-of-sight galaxies in the Hubble Frontier Fields

“…Note: a flag of −1 in the z column denotes that it is a cluster member which was photometrically selected. Mahler et al (2018). Notes are as follows: a = All teams ranked the image as secure, but redshift was tentative.…”

“…Notes are as follows: a = All teams ranked the image as secure, but redshift was tentative. b = This image did not have enough votes to obtain a ranking, but Mahler et al (2018) report a redshift. c = This image did not have enough votes to obtain a ranking.…”