Mass Modeling of Frontier Fields Cluster MACS J1149.5+2223 Using Strong and Weak Lensing

TL;DR

This paper models the mass distribution of the MACS J1149.5+2223 galaxy cluster using strong and weak gravitational lensing data, providing detailed mass maps and stellar mass fraction estimates, and comparing these to other clusters.

Contribution

It presents a comprehensive gravitational lensing model combining multiple data sources and provides the first detailed stellar mass fraction map for this cluster.

Findings

Good agreement with recent models within the HST field of view

Stellar mass fraction peaks on the primary BCG

MACS1149 has a higher stellar mass fraction than other studied clusters

Abstract

We present a gravitational lensing model of MACS J1149.5+2223 using ultra-deep Hubble Frontier Fields imaging data and spectroscopic redshifts from HST grism and VLT/MUSE spectroscopic data. We create total mass maps using 38 multiple images (13 sources) and 608 weak lensing galaxies, as well as 100 multiple images of 31 star-forming regions in the galaxy that hosts Supernova Refsdal. We find good agreement with a range of recent models within the HST field of view. We present a map of the ratio of projected stellar mass to total mass ($f_{\star}$), and find that the stellar mass fraction for this cluster peaks on the primary BCG. Averaging within a radius of 0.3 Mpc, we obtain a value of $\langle f_{\star} \rangle = 0.012^{+0.004}_{-0.003}$, consistent with other recent results for this ratio in cluster environments, though with a large global error (up to $\delta f_{\star} = 0.005$) primarily due to the choice of an IMF. We compare values of $f_{\star}$ and measures of star formation efficiency for this cluster to other Hubble Frontier Fields clusters studied in the literature, finding that MACS1149 has a higher stellar mass fraction than these other clusters, but a star formation efficiency typical of massive clusters.