A public void catalog from the SDSS DR7 Galaxy Redshift Surveys based on the watershed transform

TL;DR

This paper presents a comprehensive public catalog of cosmic voids identified in SDSS DR7 data using an advanced watershed transform method, suitable for various survey analyses and including detailed void properties.

Contribution

It introduces a modified, boundary-aware void finder and provides two distinct catalogs for different analysis needs, enhancing void studies in large-scale structure.

Findings

Void radii range from 5 to 135 h^-1 Mpc.

Radial density profiles are consistent across different void sizes and redshifts.

Catalog includes detailed statistics and derived data products.

Abstract

We produce the most comprehensive public void catalog to date using the Sloan Digital Sky Survey Data Release 7 main sample out to redshift z=0.2 and the luminous red galaxy sample out to z=0.44. Using a modified version of the parameter-free void finder ZOBOV, we fully take into account the presence of the survey boundary and masks. Our strategy for finding voids is thus appropriate for any survey configuration. We produce two distinct catalogs: a complete catalog including voids near any masks, which would be appropriate for void galaxy surveys, and a bias-free catalog of voids away from any masks, which is necessary for analyses that require a fair sampling of void shapes and alignments. Our discovered voids have effective radii from 5 to 135 h^-1 Mpc. We discuss basic catalog statistics such as number counts and redshift distributions and describe some additional data products derived from our catalog, such as radial density profiles and projected density maps. We find that radial profiles of stacked voids show a qualitatively similar behavior across nearly two decades of void radii and throughout the full redshift range.