Mass Reconstruction using Particle Based Lensing II: Quantifying substructure with Strong+Weak lensing and X-rays

TL;DR

This paper presents a new particle-based lensing technique for detailed mass mapping of galaxy clusters, revealing substructures, comparing dark matter and gas distributions, and estimating cluster mass.

Contribution

Introduces Particle Based Lensing (PBL), a novel method for high-resolution mass reconstruction using combined strong and weak lensing data.

Findings

Detected a secondary mass peak in A1689 confirming previous observations.

Found the gas distribution to be smoother and rounder than dark matter.

Estimated the cluster mass within 1 Mpc as approximately 1.5 x 10^15 solar masses.

Abstract

We report a mass reconstruction of A1689 using Particle Based Lensing (PBL), a new technique for Strong+Weak lensing that allows a variable resolution depending on the data density and the signal-to-noise. Using PBL we also calculate the covariance matrix for the resulting mass map. The reconstruction of A1689 shows a secondary mass peak in the north-east direction confirming previous optical observations. This indicates that the central region of the cluster is still undergoing a weak merger. We have used this mass map to measure power ratios of the dark matter distribution and compared it to the X-ray distribution. We find that the power in the X-ray distribution is lower suggesting a smoother and rounder gas distribution compared to the dark matter distribution. We fitted an NFW profile to the profile derived from the mass map and we find that the lensing mass within 1 Mpc is $1.5\pm0.33\times 10^{15}M_\odot$. This is higher than the X-ray mass.