CARMA Measurements of the Sunyaev-Zel'dovich Effect in RXJ1347.5-1145

TL;DR

This paper showcases CARMA's capability to produce detailed Sunyaev-Zel'dovich effect images of galaxy clusters, revealing complex structures and providing insights into cluster physics and geometry.

Contribution

It presents high-resolution SZ imaging of RXJ1347.5-1145 using CARMA, demonstrating the instrument's ability to resolve cluster substructures and compare with X-ray models.

Findings

9% of thermal energy linked to merger-related substructure

SZ signal lower than spherical X-ray model predicts

Line-of-sight compression affects SZ amplitude

Abstract

We demonstrate the Sunyaev-Zel'dovich (SZ) effect imaging capabilities of the Combined Array for Research in Millimeter-wave Astronomy (CARMA) by presenting an SZ map of the galaxy cluster RXJ1347.5-1145. By combining data from multiple CARMA bands and configurations, we are able to capture the structure of this cluster over a wide range of angular scales, from its bulk properties to its core morphology. We find that roughly 9% of this cluster's thermal energy is associated with sub-arcminute-scale structure imparted by a merger, illustrating the value of high-resolution SZ measurements for pursuing cluster astrophysics and for understanding the scatter in SZ scaling relations. We also find that the cluster's SZ signal is lower in amplitude than suggested by a spherically-symmetric model derived from X-ray data, consistent with compression along the line of sight relative to the plane of the sky. Finally, we discuss the impact of upgrades currently in progress that will further enhance CARMA's power as an SZ imaging instrument.