juliensimon/chandra-x-ray-sources

Chandra X-Ray Source Catalog

Part of the Astronomy Datasets collection on Hugging Face.

The Chandra Source Catalog (CSC 2.1) is the definitive catalog of X-ray sources detected by NASA's Chandra X-Ray Observatory, the most powerful X-ray telescope ever built. Currently 28,132 unique sources across 24 columns.

Dataset description

The Chandra X-Ray Observatory, launched in 1999, provides the sharpest X-ray images ever achieved, with sub-arcsecond angular resolution. The Chandra Source Catalog (CSC) is a comprehensive catalog of all X-ray sources detected in Chandra observations, including positions, multi-band photometry (soft, medium, hard, broad, wide bands), hardness ratios for spectral characterization, variability flags, and source extent measurements.

CSC 2.1 covers roughly 560 square degrees of sky and includes sources from over 15,000 individual Chandra observations. The catalog is essential for multi-wavelength studies of active galactic nuclei, X-ray binaries, supernova remnants, galaxy clusters, and stellar coronae.

Quick stats

• 28,132 unique X-ray sources

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/chandra-x-ray-sources", split="train")
df = ds.to_pandas()

# Brightest sources by broad-band flux
if "flux_aper_b" in df.columns:
    top = df.nlargest(10, "flux_aper_b")[["name", "ra", "dec", "flux_aper_b"]]
    print(top)

# Sky coverage map
import matplotlib.pyplot as plt
fig, ax = plt.subplots(figsize=(12, 6))
ax.scatter(df["ra"], df["dec"], s=0.01, alpha=0.1)
ax.set_xlabel("RA (deg)")
ax.set_ylabel("Dec (deg)")
ax.invert_xaxis()
ax.set_title("Chandra Source Catalog Sky Coverage")

Data source

All data comes from the Chandra Source Catalog 2.1 (Evans et al. 2024), accessed via NASA HEASARC TAP service.

Related datasets

• erosita-erass1-xray -- eROSITA eRASS1 X-ray sources
• fermi-4fgl-dr4 -- Fermi gamma-ray sources
• pulsar-catalog -- Pulsar catalog

Pipeline

Source code: juliensimon/space-datasets

Citation

@dataset{chandra_x_ray_sources,
  author = {Simon, Julien},
  title = {Chandra X-Ray Source Catalog},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/chandra-x-ray-sources},
  note = {Based on Chandra Source Catalog 2.1 (Evans et al. 2024) via NASA HEASARC}
}

License

CC-BY-4.0