juliensimon/rosat-bright-source-catalog
ROSAT All-Sky Survey Bright Source Catalog Credit: NASA/ROSAT Part of a dataset collection on Hugging Face. Dataset description The ROSAT All-Sky Survey Bright Source Catalogue (RASS-BSC or 1RXS) contains 18,806 X-ray sources detected during the ROSAT All-Sky Survey in the soft X-ray band (0.1–2.4 keV). Published by Voges et al. (1999), it is the first complete all-sky X-ray survey performed with an imaging telescope. The ROSAT (Röntgensatellit) mission… See the full description on the dataset page: https://huggingface.co/datasets/juliensimon/rosat-bright-source-catalog.
ROSAT All-Sky Survey Bright Source Catalog
<div align="center"> <img src="banner.jpg" alt="All-sky X-ray map from ROSAT survey showing the hot universe" width="400"> <p><em>Credit: NASA/ROSAT</em></p> </div>
Part of a [dataset collection](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743) on Hugging Face.
Dataset description
The ROSAT All-Sky Survey Bright Source Catalogue (RASS-BSC or 1RXS) contains 18,806 X-ray sources detected during the ROSAT All-Sky Survey in the soft X-ray band (0.1–2.4 keV). Published by Voges et al. (1999), it is the first complete all-sky X-ray survey performed with an imaging telescope.
The ROSAT (Röntgensatellit) mission, a joint German/US/UK project, scanned the entire sky during its first six months of operation (August 1990 – February 1991) using its Position Sensitive Proportional Counter (PSPC). The resulting all-sky survey revealed the soft X-ray universe in unprecedented detail, detecting stellar coronae, cataclysmic variables, white dwarfs, neutron stars, active galactic nuclei, galaxy clusters, and supernova remnants. Each source required a detection likelihood ≥15 (~6σ significance) to be included in the bright source catalogue.
The two hardness ratios (HR1, HR2) characterise the spectral shape of each source without requiring spectral fitting. HR1 distinguishes soft thermal plasma sources (stellar coronae, <1 keV) from harder sources (AGN, X-ray binaries, >1 keV). Together they span the full ROSAT bandpass and enable quick classification of large samples. The count rate can be converted to unabsorbed flux using an assumed spectral model and the hydrogen column density toward each source.
This catalogue is the definitive soft X-ray baseline for the entire sky, used extensively for identifying counterparts of sources detected by later missions (XMM-Newton, Chandra, Swift) and for population studies of X-ray emitting classes. It complements harder X-ray catalogs such as the Swift-BAT 157-month survey (15–195 keV) and the 4XMM-DR14 serendipitous catalog (0.2–12 keV).
This dataset is suitable for tabular classification tasks.
Schema
Quick stats
- 18,806 soft X-ray sources (0.1–2.4 keV), detection likelihood ≥ 15
- 10,442 extended sources (55.5% of catalogue)
- Median exposure time: 394 s — peak count rate 328.0 ct/s (J170248.5-484719)
- Full-sky coverage; typical positional accuracy ~30 arcsec
Usage
from datasets import load_dataset
ds = load_dataset("juliensimon/rosat-bright-source-catalog", split="train")
df = ds.to_pandas()from datasets import load_dataset
ds = load_dataset("juliensimon/rosat-bright-source-catalog", split="train")
df = ds.to_pandas()
# Hardest sources (likely AGN or X-ray binaries)
hard = df[df["hardness_ratio_1"] > 0.5].sort_values("count_rate", ascending=False)
# Sky distribution
import matplotlib.pyplot as plt
import numpy as np
ra = np.where(df["ra_deg"] > 180, df["ra_deg"] - 360, df["ra_deg"])
plt.figure(figsize=(12, 5))
plt.scatter(ra, df["dec_deg"], s=0.3, alpha=0.4, c=np.log10(df["count_rate"].clip(0.01)))
plt.colorbar(label="log₁₀(count rate)")
plt.xlabel("RA (deg, centred on 0)")
plt.ylabel("Dec (deg)")
plt.title("ROSAT BSC — X-ray sky")
plt.show()Data source
https://vizier.cds.unistra.fr/viz-bin/VizieR-3?-source=IX/10A/1rxs
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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{rosat_bright_source_catalog,
title = {ROSAT All-Sky Survey Bright Source Catalog},
author = {Simon, Julien},
year = {2026},
url = {https://huggingface.co/datasets/juliensimon/rosat-bright-source-catalog},
publisher = {Hugging Face},
note = {Derived from VizieR, Centre de Données astronomiques de Strasbourg (CDS), https://vizier.cds.unistra.fr/viz-bin/VizieR-3?-source=IX/10A/1rxs}
}