GalWeight: A New and Effective Weighting Technique for Determining Galaxy Cluster and Group Membership

TL;DR

GalWeight is a novel method for accurately identifying galaxy cluster members, outperforming existing techniques in simulations and real data, applicable to various cluster types and regions.

Contribution

Introduces GalWeight, a new weighting technique that improves galaxy cluster membership determination across different cluster environments and regions.

Findings

Achieves over 98% accuracy in simulations

Outperforms four existing methods in accuracy

Successfully applied to real SDSS data

Abstract

We introduce GalWeight, a new technique for assigning galaxy cluster membership. This technique is specifically designed to simultaneously maximize the number of bona fide cluster members while minimizing the number of contaminating interlopers. The GalWeight technique can be applied to both massive galaxy clusters and poor galaxy groups. Moreover, it is effective in identifying members in both the virial and infall regions with high efficiency. We apply the GalWeight technique to MDPL2 \& Bolshoi N-body simulations, and find that it is $> 98\%$ accurate in correctly assigning cluster membership. We show that GalWeight compares very favorably against four well-known existing cluster membership techniques (shifting gapper, den Hartog, caustic, SIM). We also apply the GalWeight technique to a sample of twelve Abell clusters (including the Coma cluster) using observations from the Sloan Digital Sky Survey. We end by discussing GalWeight's potential for other astrophysical applications.