Bullet Cluster: Remarkable Revelations and Enduring Insights -- Part I

TL;DR

This paper presents high-resolution Sunyaev-Zeldovich Effect observations of the Bullet Cluster, revealing complex, displaced substructures that challenge traditional models and highlight the importance of detailed SZE imaging for understanding cluster mergers.

Contribution

It introduces a novel SZE feature offset from the X-ray peak, demonstrating the complexity of cluster dynamics through high-resolution interferometric imaging.

Findings

Discovery of a new SZE feature offset from X-ray brightness peak

Detection of complex substructures within the SZE

Identification of features at critical boundaries in the cluster

Abstract

This study unveils new insights into the Bullet Cluster through cm-wave observations made with the Australia Telescope Compact Array, focusing on the Sunyaev-Zeldovich Effect (SZE). A novel SZE feature was discovered, distinctively offset from the X-ray brightness peak, challenging conventional associations between such phenomena. The findings, achieved through high-resolution interferometric imaging, reveal complex substructures within the SZE, including significantly displaced components uncorrelated with X-ray, optical, or lensing maps. This deviation underscores the complexity within the cluster's dynamics and suggests that detailed, high-resolution SZE imaging is crucial for understanding the physics of merging clusters. We perform several tests to ensure that one of these novel and unusual features is indeed real, and that the detection of all features in the images is robust. In addition to these displacements, we find several SZE features that are tentatively located at critical boundaries in this merging cluster - these features will be discussed in the next few papers in this series. These observations pave the way for more sophisticated analyses, combining SZE and X-ray data, to decode the evolutionary mysteries of cosmic structures like the Bullet Cluster. We note here that we are discussing only one novel and peculiar feature in the observations of the cluster done in the year 2019. Further observations have revealed more features, which we shall discuss in the next few papers in this series on the Bullet cluster.