juliensimon/black-hole-catalog

Black Hole Catalog

Credit: NASA/JPL-Caltech

Part of the Astronomy Datasets collection on Hugging Face.

Catalog of 3765 known black hole systems from SIMBAD: 3 confirmed black holes, 14 candidates, and 3748 X-ray binary systems hosting black hole companions.

Dataset description

Black holes are regions of spacetime where gravity is so extreme that nothing -- not even light -- can escape once past the event horizon. Stellar-mass black holes, the primary focus of this catalog, form when massive stars (typically above 20-25 solar masses) exhaust their nuclear fuel and undergo gravitational collapse. They are most readily detected when they exist in binary systems with a companion star, accreting material that heats to millions of degrees and emits intense X-radiation. The SIMBAD classification system distinguishes confirmed black holes (BH), candidates awaiting definitive mass measurements (BH?), and the X-ray binary systems (XB*, HXB, LXB) in which black holes are found.

The distinction between high-mass X-ray binaries (HXBs) and low-mass X-ray binaries (LXBs) reflects fundamentally different evolutionary pathways and accretion physics. HXBs contain young, massive companion stars and are powered primarily by wind accretion, while LXBs involve older, low-mass companions that transfer material through Roche lobe overflow, often producing characteristic transient outbursts separated by years of quiescence. Dynamical mass measurements from radial velocity curves of the companion star are the gold standard for confirming a compact object as a black hole -- any compact object exceeding roughly 3 solar masses (the Tolman-Oppenheimer-Volkoff limit for neutron stars) is classified as a black hole.

This catalog is valuable for studying the mass distribution of stellar-mass black holes, the spatial distribution of compact objects in the Galaxy, and the population statistics that constrain binary stellar evolution models. It complements the gravitational wave event catalog, which probes the merging population, by providing the census of black holes detected through electromagnetic radiation in accreting systems.

Schema

Column	Type	Description
name	string	Primary SIMBAD identifier
ra_deg	float	Right ascension (degrees)
dec_deg	float	Declination (degrees)
object_type	string	SIMBAD type code (BH, BH?, XB*, HXB, LXB)
bh_category	string	Readable category
spectral_type	string	Spectral classification
v_mag	float	Visual magnitude
b_mag	float	Blue magnitude
k_mag	float	K-band (infrared) magnitude
distance_pc	float	Distance in parsecs
angular_size_arcmin	float	Angular size (arcmin)

Usage

from datasets import load_dataset

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

# Confirmed black holes only
confirmed = df[df["object_type"] == "BH"]

# By category
df["bh_category"].value_counts()

Update frequency

Updated weekly on Monday at 18:30 UTC via GitHub Actions.

Data source

SIMBAD Astronomical Database (CDS, Strasbourg).

Related datasets

• gravitational-wave-events — Black hole and neutron star mergers from LIGO/Virgo
• quasar-catalog — 50K quasars and AGN (supermassive black holes)
• pulsar-catalog — 4,300+ pulsars (neutron stars)

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{black_hole_catalog,
  author = {Simon, Julien},
  title = {Black Hole Catalog},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/black-hole-catalog},
  note = {Based on SIMBAD astronomical database (CDS Strasbourg)}
}