juliensimon/cosmic-void-catalog

Cosmic Void Catalog

Part of the Astronomy Datasets and Galaxies & Cosmology collections on Hugging Face.

Catalog of 1,228 cosmic voids identified in the Sloan Digital Sky Survey (SDSS), sourced from VizieR CDS Strasbourg.

Dataset description

Cosmic voids are vast underdense regions in the large-scale structure of the universe, typically 20-50 Mpc in radius. They occupy the majority of the volume of the universe and are bounded by filaments, walls, and clusters that form the cosmic web. Voids are among the cleanest cosmological laboratories available because their interiors are dominated by dark energy rather than by the complex nonlinear gravitational dynamics that govern overdense regions.

Void properties are powerful probes of fundamental physics. The void size function (abundance as a function of radius) is sensitive to the matter density parameter, sigma_8, and the dark energy equation of state. The Alcock-Paczynski test applied to stacked void shapes constrains the expansion history of the universe. Void lensing profiles measure the matter content of underdense regions and test modified gravity theories, since voids amplify the differences between general relativity and alternative theories such as f(R) gravity. The integrated Sachs-Wolfe (ISW) effect -- the late-time blueshift of CMB photons traversing growing voids -- provides independent evidence for dark energy.

This catalog enables studies of void demographics, spatial distribution, and correlations with other large-scale structure tracers. Cross-matching with galaxy surveys reveals how galaxy properties (color, morphology, star formation rate) depend on large-scale environment, testing the hypothesis that void galaxies evolve differently from their counterparts in denser regions.

Schema

Column	Type	Description
sample	string	Sample
id	int	Id
ra_deg	float	Right ascension J2000 (degrees)
dec_deg	float	Declination J2000 (degrees)
redshift	float	Void center redshift
ngal	int	Ngal
v	float	V
radius_eff_mpc	float	Effective void radius (Mpc)
nmin	float	Nmin
delmin	float	Delmin
r	float	R
prob	float	Prob
dbound	float	Dbound

Quick stats

• 1,228 cosmic voids
• Median effective radius: 54.1 Mpc
• Largest void radius: 452.7 Mpc
• Median redshift: 0.480
• Redshift range: 0.214 to 0.672

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/cosmic-void-catalog", split="train")
df = ds.to_pandas()

# Void size distribution
import matplotlib.pyplot as plt
if "radius_eff_mpc" in df.columns:
    df["radius_eff_mpc"].dropna().hist(bins=30, edgecolor="black")
    plt.xlabel("Effective Radius (Mpc)")
    plt.ylabel("Count")
    plt.title("Cosmic Void Size Distribution")

# Redshift distribution
if "redshift" in df.columns:
    df["redshift"].dropna().hist(bins=30, edgecolor="black")
    plt.xlabel("Redshift")
    plt.ylabel("Count")
    plt.title("Void Redshift Distribution")

# Sky distribution
plt.figure(figsize=(12, 6))
plt.scatter(df["ra_deg"], df["dec_deg"], s=df.get("radius_eff_mpc", 5)**2 / 50,
            alpha=0.5, c=df.get("redshift"), cmap="viridis")
plt.colorbar(label="Redshift")
plt.xlabel("RA (deg)")
plt.ylabel("Dec (deg)")
plt.title("Cosmic Void Sky Distribution")

Data source

Cosmic void catalog from the Sloan Digital Sky Survey (SDSS), accessed via VizieR, CDS Strasbourg.

Primary source: Pan D.C., Vogeley M.S., Hoyle F., Choi Y.-Y., Park C., 2012, MNRAS, 421, 926.

Update schedule

Semi-annual (January and July 1st at 07:30 UTC) via GitHub Actions.

Related datasets

• desi-dr1-redshifts -- DESI DR1 galaxy redshifts
• galaxy-clusters -- Planck SZ galaxy clusters
• pantheon-plus-sne-ia -- Pantheon+ Type Ia supernovae
• planck-sz2-clusters -- Planck SZ2 cluster catalog

Pipeline

Source code: juliensimon/space-datasets

Support

If you find this dataset useful, please give it a ❤️ on the dataset page and share feedback in the Community tab! Also consider giving a ⭐️ to the space-datasets repo.

Citation

@dataset{cosmic_void_catalog,
  author = {Simon, Julien},
  title = {Cosmic Void Catalog},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/cosmic-void-catalog},
  note = {Based on SDSS void catalogs via VizieR CDS Strasbourg}
}

License

CC-BY-4.0