Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56

TL;DR

This paper combines strong and weak gravitational lensing data from high-resolution images to produce a detailed, assumption-free mass map of the merging galaxy cluster 1E0657-56, confirming previous findings.

Contribution

It presents a high-resolution, absolute-calibration mass reconstruction of the cluster using combined lensing data without assuming physical models.

Findings

More arc candidates detected with HST ACS images.

Redshifts of sources determined from strong lens model.

Accurate mass map of the cluster's central region obtained.

Abstract

The galaxy cluster 1E0657-56 (z = 0.296) is remarkably well-suited for addressing outstanding issues in both galaxy evolution and fundamental physics. We present a reconstruction of the mass distribution from both strong and weak gravitational lensing data. Multi-color, high-resolution HST ACS images allow detection of many more arc candidates than were previously known, especially around the subcluster. Using the known redshift of one of the multiply imaged systems, we determine the remaining source redshifts using the predictive power of the strong lens model. Combining this information with shape measurements of "weakly" lensed sources, we derive a high-resolution, absolutely-calibrated mass map, using no assumptions regarding the physical properties of the underlying cluster potential. This map provides the best available quantification of the total mass of the central part of the cluster. We also confirm the result from Clowe et al. (2004,2006a).