Lens models and magnification maps of the six Hubble Frontier Fields clusters

TL;DR

This paper develops detailed strong-lensing models and magnification maps for six Hubble Frontier Fields galaxy clusters, enabling precise analysis of mass distribution and lensing effects, with an emphasis on the importance of spectroscopic redshifts.

Contribution

It provides new parametric lens models and magnification maps for six galaxy clusters, incorporating spectroscopic and photometric redshift data to improve model accuracy.

Findings

Photometric redshifts generally agree with spectroscopic redshifts.

Relaxed redshift priors may underestimate large-scale structure complexity.

Spectroscopic redshifts are crucial for high-precision lens modeling.

Abstract

We present strong-lensing models, as well as mass and magnification maps, for the cores of the six HST Frontier Fields galaxy clusters. Our parametric lens models are constrained by the locations and redshifts of multiple image systems of lensed background galaxies. We use a combination of photometric redshifts and spectroscopic redshifts of the lensed background sources obtained by us (for Abell 2744 and Abell S1063), collected from the literature, or kindly provided by the lensing community. Using our results, we (1) compare the derived mass distribution of each cluster to its light distribution, (2) quantify the cumulative magnification power of the HFF clusters, (3) describe how our models can be used to estimate the magnification and image multiplicity of lensed background sources at all redshifts and at any position within the cluster cores, and (4) discuss systematic effects and caveats resulting from our modeling methods. We specifically investigate the effect of the use of spectroscopic and photometric redshift constraints on the uncertainties of the resulting models. We find that the photometric redshift estimates of lensed galaxies are generally in excellent agreement with spectroscopic redshifts, where available. However, the flexibility associated with relaxed redshift priors may cause the complexity of large-scale structure that is needed to account for the lensing signal to be underestimated. Our findings thus underline the importance of spectroscopic arc redshifts, or tight photometric redshift constraints, for high precision lens models. All products from our best-fit lens models (magnification, convergence, shear, deflection field) and model simulations for estimating errors are made available via the Mikulski Archive for Space Telescopes.