Precise Strong Lensing Mass Modeling of Four Hubble Frontier Fields Clusters and a Sample of Magnified High-Redshift Galaxies

TL;DR

This paper presents precise strong lensing mass models for four Hubble Frontier Fields clusters, improving image reproduction accuracy and enabling detailed studies of faint high-redshift galaxies through magnification estimates.

Contribution

The study provides refined mass models for four HFF clusters using a large sample of multiple images, achieving lower RMS errors and predicting new lensed images, enhancing the understanding of cluster lensing effects.

Findings

Mass models reproduce observed images with RMS errors of ~0.4 arcsec.

Predicted a new image of SN Refsdal consistent with observations.

Identified ~120 high-redshift galaxies, with about 20 magnified by over 10 times.

Abstract

We conduct precise strong lensing mass modeling of four ${\it Hubble}$ Frontier Fields (HFF) clusters, Abell$~$2744, MACS$~$J0416.1$-$2403, MACS$~$J0717.5$+$3745, and MACS$~$J1149.6$+$2223, for which HFF imaging observations are completed. We construct a refined sample of more than 100 multiple images for each cluster by taking advantage of the full depth HFF images, and conduct mass modeling using the ${\small \rm GLAFIC}$ software, which assumes simply parametrized mass distributions. Our mass modeling also exploits a magnification constraint from the lensed Type Ia supernova HFF14Tom for Abell$~$2744 and positional constraints from the multiple images S1$-$S4 of the lensed supernova SN Refsdal for MACS$~$J1149.6$+$2223. We find that our best-fitting mass models reproduce the observed image positions with RMS errors of $\sim 0.4$ arcsec, which are smaller than RMS errors in previous mass modeling that adopted similar numbers of multiple images. Our model predicts a new image of SN Refsdal with a relative time delay and magnification that are fully consistent with a recent detection of reappearance. We then construct catalogs of $z\sim 6-9$ dropout galaxies behind the four clusters and estimate magnification factors for these dropout galaxies with our best-fitting mass models. The dropout sample from the four cluster fields contains $\sim 120$ galaxies at $z\gtrsim 6$, about 20 of which are predicted to be magnified by a factor of more than 10. Some of the high-redshift galaxies detected in the HFF have lensing-corrected magnitudes of $M_{\rm UV}\sim -15$ to $-14$. Our analysis demonstrates that the HFF data indeed offer an ideal opportunity to study faint high-redshift galaxies. All lensing maps produced from our mass modeling will be made available on the STScI website.