Shear-Selected Clusters From the Deep Lens Survey III: Masses from Weak Lensing

TL;DR

This paper estimates the masses of seven shear-selected galaxy clusters from the Deep Lens Survey using weak lensing, confirming the viability of shear selection for cluster detection and discussing associated challenges.

Contribution

It provides weak lensing mass estimates for shear-selected clusters, demonstrating the method's effectiveness and addressing issues like profile assumptions and line-of-sight projections.

Findings

Masses range from 250-800 km/s velocity dispersion.

Results are consistent across different profile assumptions.

Shear selection is validated as a cluster detection technique.

Abstract

We present weak lensing mass estimates of seven shear-selected galaxy cluster candidates from the Deep Lens Survey. The clusters were previously identified as mass peaks in convergence maps of 8.6 sq. deg of R band imaging, and followed up with X-ray and spectroscopic confirmation, spanning a redshift range 0.19 - 0.68. Most clusters contained multiple X-ray peaks, yielding 17 total mass concentrations. In this paper, we constrain the masses of these X-ray sources with weak lensing, using photometric redshifts from the full set of BVRz' imaging to properly weight background galaxies according to their lensing distance ratios. We fit both NFW and singular isothermal sphere profiles, and find that the results are insensitive to the assumed profile. We also show that the results do not depend significantly on the assumed prior on the position of the mass peak, but that this may become an issue in future larger samples. The inferred velocity dispersions for the extended X-ray sources range from 250-800 km/s, with the exception of one source for which no lensing signal was found. This work further establishes shear selection as a viable technique for finding clusters, but also highlights some unresolved issues such as determination of the mass profile center without biasing the mass estimate, and fully accounting for line-of-sight projections. A follow-up paper will examine the mass-X-ray scaling relations of these clusters.