juliensimon/swift-bat-hard-xray-survey
Swift-BAT 157-Month Hard X-Ray Survey Credit: NASA/JPL-Caltech/STScI/CXC/SAO Part of a dataset collection on Hugging Face. Dataset description Catalog of hard X-ray sources detected in the 14–195 keV band by the Swift Burst Alert Telescope (BAT) over 157 months of all-sky survey observations. The survey represents over 13 years of continuous monitoring of the hard X-ray sky, providing positions, fluxes, and spectral parameters for AGN, X-ray binaries… See the full description on the dataset page: https://huggingface.co/datasets/juliensimon/swift-bat-hard-xray-survey.
Swift-BAT 157-Month Hard X-Ray Survey
<div align="center"> <img src="banner.jpg" alt="Cassiopeia A supernova remnant in X-ray, optical, and infrared light" width="400"> <p><em>Credit: NASA/JPL-Caltech/STScI/CXC/SAO</em></p> </div>
Part of a [dataset collection](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743) on Hugging Face.
Dataset description
Catalog of hard X-ray sources detected in the 14–195 keV band by the Swift Burst Alert Telescope (BAT) over 157 months of all-sky survey observations. The survey represents over 13 years of continuous monitoring of the hard X-ray sky, providing positions, fluxes, and spectral parameters for AGN, X-ray binaries, galaxy clusters, and other high-energy sources sourced from NASA HEASARC.
The Swift-BAT hard X-ray survey is the most sensitive and uniform survey of the sky in the 14–195 keV energy band. BAT is a coded-aperture instrument aboard the Neil Gehrels Swift Observatory that continuously monitors the hard X-ray sky. The 157-month catalog reaches a sensitivity of approximately 8×10⁻¹² erg/cm²/s over most of the sky, probing the hard X-ray luminosity function down to Seyfert-level AGN in the local universe.
Hard X-rays penetrate gas and dust that absorb softer X-rays, making BAT uniquely suited for finding obscured AGN and mapping the local hard X-ray universe. The source population is dominated by active galactic nuclei — both unobscured (Seyfert 1) and obscured (Seyfert 2) — because the 14–195 keV band penetrates Compton-thin absorption (column densities up to N_H ~ 10²⁴ cm⁻²). The BAT AGN sample has been foundational for measuring the intrinsic fraction of obscured AGN as a function of luminosity and redshift, directly constraining models of AGN unification and the cosmic X-ray background.
The spectral parameters — photon indices and fluxes — derived from the time-averaged BAT spectra provide a clean, absorption-independent measure of intrinsic source luminosity. Combined with redshifts, these yield hard X-ray luminosities that anchor the X-ray luminosity function of AGN, a fundamental input to models of supermassive black hole growth and the synthesis of the cosmic X-ray background.
This dataset is suitable for tabular classification tasks.
Schema
Quick stats
- 1,891 hard X-ray sources detected in the 14–195 keV band
- 1,098 sources with measured redshifts (58% of total)
- 1,213 active galactic nuclei (AGN/Seyfert sources)
- 1,708 sources with multi-wavelength counterpart identifications
- Median detection SNR: 7.2
- Survey coverage: 157 months (~13 years) of Swift BAT all-sky monitoring
Usage
from datasets import load_dataset
ds = load_dataset("juliensimon/swift-bat-hard-xray-survey", split="train")
df = ds.to_pandas()from datasets import load_dataset
import matplotlib.pyplot as plt
import numpy as np
ds = load_dataset("juliensimon/swift-bat-hard-xray-survey", split="train")
df = ds.to_pandas()
# All-sky Mollweide map of hard X-ray sources
fig = plt.figure(figsize=(12, 6))
ax = fig.add_subplot(111, projection="mollweide")
ra_rad = np.deg2rad(df["ra"] - 180)
dec_rad = np.deg2rad(df["dec"])
scatter = ax.scatter(ra_rad, dec_rad, c=np.log10(df["snr"].clip(lower=0.1)),
s=3, alpha=0.6, cmap="plasma")
plt.colorbar(scatter, ax=ax, label="log10(SNR)")
ax.set_title("Swift-BAT Hard X-Ray Sources (14-195 keV)")
ax.grid(True)
plt.tight_layout()
plt.savefig("swift_bat_skymap.png", dpi=150)
plt.show()
# Top 10 brightest sources
top10 = df.nlargest(10, "snr")[["name", "snr", "flux", "source_type", "redshift"]]
print("\nTop 10 brightest hard X-ray sources:")
print(top10.to_string(index=False))
# Photon index distribution for AGN
agn = df[df["source_type"].str.contains("Sy|AGN", case=False, na=False)]
plt.figure(figsize=(8, 4))
agn["spectral_index"].dropna().hist(bins=40, edgecolor="k")
plt.xlabel("Photon Index Γ")
plt.ylabel("Count")
plt.title(f"Photon Index Distribution for {len(agn):,} BAT AGN")
plt.tight_layout()
plt.show()Data source
https://heasarc.gsfc.nasa.gov/xamin/vo/tap/
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About the author
Created by Julien Simon — AI Operating Partner at Fortino Capital. Part of the Space Datasets collection.
Citation
@dataset{swift_bat_hard_xray_survey,
title = {Swift-BAT 157-Month Hard X-Ray Survey},
author = {Simon, Julien},
year = {2026},
url = {https://huggingface.co/datasets/juliensimon/swift-bat-hard-xray-survey},
publisher = {Hugging Face},
note = {Derived from NASA HEASARC (High Energy Astrophysics Science Archive Research Center), https://heasarc.gsfc.nasa.gov/xamin/vo/tap/}
}