The spectroscopically confirmed huge cosmic structure at z=0.55

TL;DR

This paper reports the spectroscopic confirmation of a massive, extensive cosmic structure at redshift 0.55, highlighting its richness and potential for studying galaxy evolution and large-scale environmental effects.

Contribution

First spectroscopic confirmation of a large, rich cosmic structure at z=0.55, combining wide-field imaging, spectroscopy, and X-ray observations.

Findings

Confirmed 14 systems near the cluster redshift.

Detected extended X-ray emissions from 70% of systems.

Identified over 30 galaxy concentrations around the cluster.

Abstract

We report on the spectroscopic confirmation of a huge cosmic structure around the CL0016 cluster at z=0.55. We made wide-field imaging observations of the surrounding regions of the cluster and identified more than 30 concentrations of red galaxies near the cluster redshift. The follow-up spectroscopic observations of the most prominent part of the structure confirmed 14 systems close to the cluster redshift, roughly half of which have a positive probability of being bound to the cluster dynamically. We also made an X-ray follow-up, which detected extended X-ray emissions from 70% of the systems in the X-ray surveyed region. The observed structure is among the richest ever observed in the distant Universe. It will be an ideal site for quantifying environmental variations in the galaxy properties and effects of large-scale structure on galaxy evolution.