Weak Lensing analysis of Abell 2390 using short exposures

TL;DR

This paper demonstrates a weak lensing analysis of Abell 2390 using short exposures, validating the method with simulations, and revealing detailed mass structures consistent with other observations.

Contribution

It introduces a shape measurement pipeline for short exposure images and applies it to map the mass distribution of Abell 2390, confirming its effectiveness.

Findings

Mass of Abell 2390 agrees with previous studies

E-Mode maps reveal filamentary structures and galaxy groups

Central bimodal mass distribution consistent with X-Ray data

Abstract

We present a weak lensing analysis of the galaxy cluster Abell 2390 at z = 0.23 using second moment shape measurements made in 411 short 60s exposures. The exposures are obtained in three broadband photometric filters (g, r, i) using WIYN-ODI. Shape measurement in individual exposures is done using a moment matching algorithm. Forced measurement is used when the moment matching algorithm fails to converge at low signal to noise ratio (SNR). The measurements made in individual images are combined using inverse error weight to obtain accurate shape of sources and hence recover shear. We use PhoSim simulations to validate shear measurements recovered by our pipeline. We find the mass of Abell 2390 is in agreement with previously published results. We also find the E-Mode maps show filamentary structures consistent with baryonic structures and recovers most clusters/groups of galaxies found using Optical and X-Ray data. Thus we demonstrate the feasibility of using Weak Lensing to map large scale structure of the universe. We also find the central portion of the cluster has a bimodal mass distribution and the relative orientation of the peaks are similar to X-Ray. We discuss earlier research on this galaxy cluster and show that a late stage merger accounts for all the observed data.