juliensimon/galaxy-clusters

---
license: cc-by-4.0
pretty_name: "Planck PSZ2 Galaxy Cluster Catalog"
language:
- en
description: "Galaxy clusters detected by the Planck satellite via the Sunyaev-Zel'dovich effect with mass, redshift, and signal-to-noise"
task_categories:
- tabular-regression
tags:
- galaxy-cluster
- planck
- sz-effect
- cosmology
- astronomy
- open-data
size_categories:
- 1K<n<10K
---

# Planck PSZ2 Galaxy Cluster Catalog

![Updated](https://img.shields.io/badge/dynamic/json?url=https://raw.githubusercontent.com/juliensimon/space-datasets/main/status.json&query=$["galaxy-clusters"]&label=updated&color=brightgreen)

Complete catalog of galaxy clusters detected by the
[Planck satellite](https://www.cosmos.esa.int/web/planck) via the Sunyaev-Zel'dovich (SZ)
effect, sourced via NASA HEASARC. Currently **1,655** clusters.

## Dataset description

Galaxy clusters are the largest gravitationally bound structures in the universe. The
Planck satellite detected them through the thermal Sunyaev-Zel'dovich effect: hot
intracluster gas distorts the cosmic microwave background spectrum. The PSZ2 catalog is
the second and final Planck SZ source catalog, based on the full mission data.

This dataset includes positions, redshifts, SZ-derived mass proxies, integrated SZ
signal, signal-to-noise ratio, and detection pipeline information.

## Schema

| Column | Type | Description |
|--------|------|-------------|
| `name` | string | Planck cluster name (e.g. "PSZ2 G000.13+78.04") |
| `ra` | float | Right ascension (degrees) |
| `dec` | float | Declination (degrees) |
| `lii` | float | Galactic longitude (degrees) |
| `bii` | float | Galactic latitude (degrees) |
| `redshift` | float | Cluster redshift |
| `redshift_source_name` | string | Source of redshift measurement |
| `mass_sz` | float | SZ mass proxy M_SZ (10^14 solar masses) |
| `mass_sz_pos_err` | float | Mass proxy positive uncertainty |
| `mass_sz_neg_err` | float | Mass proxy negative uncertainty |
| `y5r500` | float | Integrated SZ signal Y_5R500 (arcmin^2) |
| `y5r500_error` | float | SZ signal uncertainty |
| `snr` | float | Detection signal-to-noise ratio |
| `det_pipeline_codes` | string | Detection pipeline code(s) used |

## Quick stats

- **1,655** galaxy clusters
- **1,094** with measured redshift (median z = 0.224, max z = 0.972)
- Median detection SNR: **5.6**

## Usage

```python
from datasets import load_dataset

ds = load_dataset("juliensimon/galaxy-clusters", split="train")
df = ds.to_pandas()

# Redshift distribution
z = df["redshift"].dropna()
print(f"{len(z):,} clusters with redshift, median z = {z.median():.3f}")

# Most massive clusters
top = df.nlargest(10, "mass_sz")[["name", "redshift", "mass_sz", "snr"]]

# Sky map in Galactic coordinates
import matplotlib.pyplot as plt
plt.scatter(df["lii"], df["bii"], c=df["snr"], s=3, cmap="viridis")
plt.colorbar(label="SNR")
plt.xlabel("Galactic longitude (deg)")
plt.ylabel("Galactic latitude (deg)")
plt.title("Planck PSZ2 Galaxy Clusters")
```

## Data source

All data comes from the [Planck PSZ2 Catalog](https://heasarc.gsfc.nasa.gov/W3Browse/all/plancksz2.html)
hosted by NASA's High Energy Astrophysics Science Archive Research Center (HEASARC),
accessed via the TAP protocol.

Original reference: Planck Collaboration, 2016, A&A, 594, A27.

## Update schedule

Quarterly (1st Monday of January, April, July, October at 19:30 UTC) via
[GitHub Actions](https://github.com/juliensimon/space-datasets).

## Related datasets

- [supernova-remnants](https://huggingface.co/datasets/juliensimon/supernova-remnants) — Green's SNR Catalog
- [gamma-ray-bursts](https://huggingface.co/datasets/juliensimon/gamma-ray-bursts) — Fermi GBM GRB Catalog
- [exoplanets](https://huggingface.co/datasets/juliensimon/exoplanets) — NASA Exoplanet Archive

## Pipeline

Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)

## Citation

```bibtex
@dataset{galaxy_clusters,
author = {Simon, Julien},
title = {Planck PSZ2 Galaxy Cluster Catalog},
year = {2026},
publisher = {Hugging Face},
url = {https://huggingface.co/datasets/juliensimon/galaxy-clusters},
note = {Based on Planck PSZ2 Catalog via NASA HEASARC}
}
```

## License

[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)