The Distance and Peculiar Velocity of the Norma Cluster (ACO3627) Using the Near-infrared J- and Ks-band Fundamental Plane Relations

Abstract

We report distance measurements for the Norma cluster based on the near-infrared J- and Ks-band fundamental plane (FP) relations. Our simultaneous J- and Ks-band photometry analyses were performed using 31 early-type galaxies in the nearby Norma cluster obtained using the 1.4m InfraRed Survey Facility (IRSF) at the South African Astronomical Observatory. Our final Ks-band FP sample consists of 41 early-type galaxies from the Norma cluster observed using the IRSF and the New Technology Telescope (NTT) at the European Southern Observatory. This is the largest cluster sample used for peculiar velocity studies in the Great Attractor region to date. From the Ks-band FP, we find a distance to the Norma cluster of 4915±121kms−1. The implied peculiar velocity for Norma is 44±151kms−1, which further supports a small peculiar velocity for the Norma cluster.