The candidate cluster and protocluster catalog (CCPC) II: Spectroscopically identified structures spanning 2 < z < 6.6

TL;DR

This paper expands the catalog of spectroscopically confirmed galaxy protoclusters from redshift 2 to 6.6, identifying 173 new candidates and the most distant known at z=6.56, enhancing understanding of early universe structure formation.

Contribution

It significantly enlarges the spectroscopic protocluster catalog, including the most distant candidate at z=6.56, providing valuable data for studying early cosmic structures.

Findings

Identified 173 new protocluster candidates at 2 < z < 6.6.

Discovered the most distant protocluster candidate at z=6.56.

Found multiple proto-supercluster candidates at various redshifts.

Abstract

The Candidate Cluster and Protocluster Catalog (CCPC) is a list of objects at redshifts z > 2 composed of galaxies with spectroscopically confirmed redshifts that are coincident on the sky and in redshift. These protoclusters are identified by searching for groups in volumes corresponding to the expected size of the most massive protoclusters at these redshifts. In CCPC1 we identified 43 candidate protoclusters among 14,000 galaxies between 2.74 < z < 3.71. Here we expand our search to more than 40,000 galaxies with spectroscopic redshifts z > 2.00, resulting in an additional 173 candidate structures. The most significant of these are 36 protoclusters with overdensities {\delta} > 7. We also identify three large proto-supercluster candidates containing multiple protoclusters at z = 2.3, 3.5 and z = 6.56. Eight candidates with N > 10 or more galaxies are found at redshifts z > 4.0. The last system in the catalog is the most distant spectroscopic protocluster candidate known to date at z = 6.56.