juliensimon/black-hole-catalog

Black Hole Catalog

Credit: NASA/JPL-Caltech

Part of a dataset collection on Hugging Face.

Dataset description

Catalog of known black hole systems — confirmed black holes, candidates, and X-ray binaries from the SIMBAD astronomical database.

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.

This dataset is suitable for tabular classification tasks.

Schema

Column	Type	Description	Sample	Null %
name	string	Primary SIMBAD identifier or common name (e.g. 'Cyg X-1', 'GRS 1915+105'); the canonical designation used in the astronomical literature for cross-matching	* 14 Aur B	0.0%
ra_deg	float64	ICRS J2000.0 right ascension in degrees (0-360); useful for positional cross-matching with X-ray, radio, and optical surveys	78.84833369455	0.2%
dec_deg	float64	ICRS J2000.0 declination in degrees (-90 to +90)	32.68478675825	0.2%
object_type	string	SIMBAD classification code: 'BH' = confirmed black hole, 'BH?' = black hole candidate awaiting definitive mass measurement, 'XB*' = generic X-ray binary, 'HXB' = high-mass X-ray binary (massive companion, wind accretion), 'LXB' = low-mass X-ray binary (Roche lobe overflow, often transient)	XB*	0.0%
spectral_type	string	MK spectral classification of the companion or donor star (e.g. 'O9.7Iab' for Cyg X-1); indicates companion mass and evolutionary state; null for systems without spectroscopic data or for isolated black holes	F2V+DA1.3	91.8%
bh_category	string	Human-readable expansion of object_type; one of 'Confirmed Black Hole', 'Black Hole Candidate', 'X-ray Binary', 'High-Mass X-ray Binary', 'Low-Mass X-ray Binary', 'Other'	X-ray Binary	0.0%

Quick stats

• 3765 black hole systems total
• 3 confirmed black holes
• 14 black hole candidates
• 3748 X-ray binary systems hosting black hole companions

Usage

from datasets import load_dataset

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

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"]
print(f"{len(confirmed)} confirmed black holes")

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

# Category distribution plot
import matplotlib.pyplot as plt
df["bh_category"].value_counts().plot.barh()
plt.xlabel("Count")
plt.title("Black Hole Systems by Category")
plt.tight_layout()
plt.show()

Data source

https://simbad.u-strasbg.fr/

Related datasets

• juliensimon/gravitational-wave-events

• juliensimon/quasar-catalog

• juliensimon/pulsar-catalog

If you find this dataset useful, please consider giving it a like on Hugging Face. It helps others discover it.

About the author

Created by Julien Simon — AI Operating Partner at Fortino Capital. Part of the Space Datasets collection.

Citation

@dataset{black_hole_catalog,
  title = {Black Hole Catalog},
  author = {juliensimon},
  year = {2026},
  url = {https://huggingface.co/datasets/juliensimon/black-hole-catalog},
  publisher = {Hugging Face}
}

License

CC-BY-4.0