The KALEIDOSCOPE survey : A new strong and weak gravitational lensing view of the massive galaxy cluster MACS J1423.8+2404

TL;DR

This study combines strong and weak gravitational lensing data from HST and VLT to map the mass distribution of the relaxed galaxy cluster MACS J1423.8+2404, providing precise mass estimates and confirming its dynamical relaxation.

Contribution

It presents a comprehensive lensing analysis of MACS J1423 using combined strong and weak lensing data, offering detailed mass measurements and confirming the cluster's relaxed state.

Findings

Projected mass within 200 kpc is (1.6 ± 0.05) × 10^{14} M_sun

Projected mass within 640 kpc is (6.6 ± 0.6) × 10^{14} M_sun

No evidence of substructures, indicating a relaxed cluster

Abstract

We present a combined strong and weak gravitational-lensing analysis of the massive galaxy cluster MACS J1423.8+2404 ($z=0.545$, MACS J1423 hereafter), one of the most dynamically relaxed and massive cool-core clusters discovered in the MAssive Cluster Survey at $z>0.5$. We combine high-resolution imaging from the Hubble Space Telescope (HST) in the F606W, F814W, and F160W pass-bands with spectroscopic observations taken as part of the KALEIDOSCOPE survey with the Multi-Unit Spectroscopic Explorer mounted on the Very Large Telescope. Our strong lensing analysis of the mass distribution in the cluster core is constrained by four multiple-image systems (17 individual images) within redshift range $1.779<z<2.840$. Our weak-lensing analysis of the cluster outskirts, confined to the HST field of view, is based on a background galaxy catalogue with a density of 57 gal.arcmin$^{-2}$. We measure a projected mass of M($\textrm{R}<200$ kpc) = (1.6 $\pm$ 0.05) $\times$ 10$^{14}$ M$_{\rm\odot}$ from our strong-lensing model, and a projected mass of M($\textrm{R}<640$ kpc) = (6.6 $\pm$ 0.6) $\times$ 10$^{14}$ M$_{\rm\odot}$ when combining with our the weak-lensing constraints. Our analysis of the cluster mass distribution yields no evidence of substructures, confirming the dynamically relaxed state of MACS J1423. Our work sets the stage for future analysis of MACS J1423 in the upcoming Canadian Near Infrared Imager and Stiltless Spectrograph Unbiased Cluster Survey for the James Webb Space Telescope.