Datasets:

juliensimon
/

rosat-bright-source-catalog

iau_name large_stringlengths 16 16	ra_deg float64 0 360	dec_deg float64 -89 88.7	pos_error_arcsec float64 6 75 ⌀	count_rate float64 0.05 328 ⌀	count_rate_err float64 0 3.99 ⌀	bg_count_rate float64 0 0 ⌀	exp_time_s float64 17 17.2k ⌀	hardness_ratio_1 float64 -1 1	hardness_ratio_1_err float64 0 0.52	hardness_ratio_2 float64 -1 1	hardness_ratio_2_err float64 0 9.99	source_extent int64 0 347	extent_likelihood float64 1 10k ⌀	detection_likelihood float64 15 10k ⌀	extent_radius_arcsec int64 300 18k	spectral_band large_stringclasses 3 values	vignetting_factor float64 0.57 0.88 ⌀	num_candidates int64 0 976
J030145.1+011538	45.43792	1.26056	13	0.1039	0.02598	0.000957	181	0.44	0.23	0.08	0.27	10	1	40	300	b	0.78	11
J030136.9+015517	45.40375	1.92139	13	0.2053	0.03267	0.000892	210	0.9	0.07	0.57	0.13	23	8	101	300	b	0.69	15
J030806.3+023900	47.02625	2.65014	12	0.08479	0.01724	0.001271	363	1	0.11	0.53	0.16	19	4	49	300	b	0.73	2
J030322.7+015549	45.84459	1.93042	13	0.1589	0.02934	0.000974	222	0.89	0.14	0.33	0.17	0	null	70	300	b	0.69	13
J030437.1+025706	46.15458	2.95167	14	0.09274	0.02222	0.000966	283	-0.97	0.06	1	9.99	10	1	26	300	b	0.73	7
J030030.3+024104	45.12625	2.68458	12	0.07241	0.01994	0.000844	222	0.67	0.22	-0.22	0.28	9	1	36	300	b	0.78	9
J031313.0+034924	48.30417	3.82333	8	0.3122	0.02823	0.001049	453	-0.06	0.08	-0.12	0.12	10	1	342	300	b	0.75	7
J030910.2+032341	47.2925	3.39486	12	0.05609	0.01331	0.001036	431	0.65	0.21	0.48	0.21	0	null	38	300	b	0.73	9
J030825.9+040637	47.10792	4.11042	9	0.1747	0.02143	0.000973	444	0.91	0.05	0.08	0.11	19	5	181	300	b	0.73	14
J031326.9+050022	48.36208	5.00625	15	0.05203	0.01328	0.001022	395	0.88	0.14	0.29	0.23	12	1	29	300	b	0.72	4
J031422.7+062001	48.59458	6.33375	8	0.5309	0.04324	0.000973	296	0.96	0.02	0.15	0.07	23	16	485	300	b	0.71	6
J031226.2+063933	48.10917	6.65931	15	0.09087	0.0173	0.00083	382	0.75	0.15	0.31	0.18	24	4	56	300	b	0.69	6
J024215.2+053037	40.56333	5.51028	8	0.4861	0.05029	0.001471	215	0.56	0.09	0.18	0.11	0	null	289	300	b	0.72	8
J024614.7+053537	41.56125	5.59375	24	0.1686	0.04846	0.001712	101	-0.49	0.24	-0.16	1.08	0	null	21	300	b	0.71	7
J030330.0+055425	45.875	5.90694	10	0.2682	0.03004	0.00084	326	0.87	0.07	0.19	0.11	21	9	201	300	b	0.7	5
J025732.7+060107	44.38625	6.01875	13	0.4484	0.02608	0.001016	255	1	0.1	0.71	0.09	0	null	42	540	b	0.71	50
J030004.3+074508	45.01792	7.75236	14	0.05781	0.01689	0.000879	278	-0.23	0.26	-0.26	0.69	0	null	23	300	b	0.74	9
J033108.2+071325	52.78417	7.22375	9	0.2758	0.03022	0.00113	382	-0.25	0.09	0.16	0.16	16	1	193	300	b	0.72	13
J032350.5+071746	50.96041	7.29611	8	0.1553	0.01819	0.000998	520	0.96	0.05	0.1	0.11	16	7	207	300	b	0.73	4
J031138.4+071357	47.91	7.2325	28	0.06408	0.01328	0.000784	386	0.57	0.21	0.78	0.15	66	12	32	300	b	0.68	2
J031732.3+074123	49.38458	7.68972	15	0.09819	0.02141	0.000887	292	-0.57	0.17	-0.42	0.42	19	2	35	300	b	0.76	11
J032046.5+084117	50.19375	8.68806	13	0.09737	0.01546	0.000908	460	0.9	0.1	0.23	0.15	24	5	70	300	b	0.71	6
J032143.0+084546	50.42916	8.76278	16	0.0584	0.01278	0.000945	488	-0.05	0.21	0.05	0.28	21	2	35	300	b	0.73	6
J033841.1+095824	54.67125	9.97333	11	2.78	0.1274	0.000828	400	1	0.01	0.64	0.05	84	219	519	945	b	0.7	22
J032709.8+094410	51.79084	9.73611	7	0.7654	0.07526	0.001035	459	0.12	0.09	0.13	0.12	0	null	287	300	b	0.74	9
J033310.7+103613	53.29459	10.60361	12	0.0516	0.0136	0.000658	372	0.38	0.26	0.43	0.27	0	null	33	300	b	0.69	5
J031257.2+082236	48.23833	8.37681	32	0.1645	0.02934	0.000792	236	1	0.17	0.94	0.15	104	29	23	300	b	0.71	8
J031611.4+090445	49.0475	9.07931	10	0.1408	0.02298	0.000904	303	0.87	0.08	0.3	0.15	0	null	103	300	b	0.73	6
J031232.3+094426	48.13458	9.74069	18	0.0865	0.02298	0.000909	222	-0.19	0.23	-0.25	0.34	17	1	26	300	b	0.75	5
J030633.3+103057	46.63875	10.51583	15	0.05649	0.01349	0.000848	407	0.15	0.24	0.34	0.29	20	2	35	300	b	0.73	0
J030855.8+110320	47.2325	11.05569	12	0.06775	0.0187	0.000916	252	1	0.21	0.44	0.22	0	null	35	300	b	0.68	6
J032322.4+114122	50.84333	11.68958	9	0.1026	0.01613	0.001173	540	-0.19	0.14	0.22	0.21	0	null	82	300	b	0.73	5
J032802.3+111441	52.00959	11.24472	13	0.05736	0.01421	0.000851	406	-0.37	0.21	0.02	0.39	0	null	31	300	b	0.72	3
J032620.8+113106	51.58667	11.51847	10	0.09322	0.01627	0.000996	448	-0.16	0.16	-0.07	0.24	8	1	75	300	b	0.73	7
J031446.7+112738	48.69458	11.46069	12	0.06524	0.01621	0.000864	350	-0.46	0.19	0.55	0.7	0	null	33	300	b	0.72	10
J032409.7+123745	51.04042	12.62931	10	0.0551	0.01231	0.001051	507	0.83	0.15	0	0.21	0	null	44	300	b	0.71	9
J031924.8+124740	49.85333	12.79458	9	0.1478	0.017	0.001079	560	0.58	0.1	0.09	0.12	16	2	176	300	b	0.73	11
J023809.6+051210	39.54	5.20278	14	0.07686	0.02227	0.001354	213	-0.01	0.28	0.25	0.39	0	null	24	300	b	0.76	5
J024126.0+055923	40.35833	5.98972	10	0.5573	0.05445	0.00148	224	-0.19	0.09	0.36	0.14	24	5	253	300	b	0.72	9
J024135.2+071117	40.39667	7.18806	9	0.1466	0.029	0.0016	198	0.78	0.15	0.26	0.21	0	null	75	300	b	0.81	11
J024214.5+074442	40.56042	7.745	16	0.09848	0.02849	0.001589	154	0.74	0.27	0.17	0.3	17	1	25	300	b	0.77	7
J023245.8+063706	38.19083	6.61833	32	0.1435	0.0294	0.001244	232	0.98	0.24	-0.22	0.28	82	12	24	300	b	0.72	6
J023213.4+064948	38.05583	6.83	15	0.08863	0.02249	0.001218	225	0.51	0.22	-0.15	0.32	11	1	31	300	b	0.75	4
J022859.6+072007	37.24833	7.33542	32	0.09626	0.02391	0.001066	230	0.61	0.24	0.31	0.26	49	2	23	300	b	0.7	5
J023601.9+082124	39.00792	8.35667	9	0.09224	0.02306	0.001393	227	0.23	0.26	0.2	0.3	5	1	39	300	b	0.76	4
J024952.1+085636	42.46708	8.94347	11	0.09594	0.02787	0.000852	157	0.74	0.29	-0.67	0.37	0	null	32	300	b	0.72	9
J025514.5+090655	43.81042	9.11542	14	0.05946	0.01868	0.000938	261	0.95	0.17	-0.18	0.3	0	null	20	300	b	0.69	10
J025726.6+093020	44.36083	9.50556	17	0.106	0.02173	0.000926	280	-0.08	0.19	0.27	0.26	27	1	43	300	b	0.75	8
J025552.4+091853	43.96833	9.31472	10	0.08261	0.01894	0.000937	277	1	0.14	0.42	0.2	0	null	44	300	b	0.76	6
J025251.1+104030	43.21292	10.67514	14	0.06717	0.01697	0.000801	288	1	0.28	0.95	0.29	0	null	36	300	b	0.69	6
J022231.7+110603	35.63208	11.10083	20	0.08042	0.0212	0.000951	258	-0.25	0.23	-0.12	0.41	0	null	22	300	b	0.67	12
J025659.9+101912	44.24958	10.32014	16	0.07177	0.01813	0.000897	289	0.27	0.24	0.06	0.29	0	null	28	300	b	0.73	6
J030122.7+112345	45.34458	11.39597	10	0.1172	0.01818	0.000825	436	-0.1	0.15	0.41	0.2	14	4	93	300	b	0.72	6
J025751.8+115759	44.46583	11.96653	12	0.09668	0.01895	0.000922	344	0.12	0.2	0.13	0.26	13	1	56	300	b	0.73	2
J025029.9+115206	42.62458	11.86847	8	0.5687	0.04783	0.000832	277	0.29	0.07	0.21	0.1	16	9	494	300	b	0.74	8
J025750.7+130243	44.46125	13.04528	11	0.3076	0.03303	0.001137	355	0.92	0.05	0.14	0.09	0	null	188	300	b	0.73	42
J025858.2+133449	44.7425	13.58042	10	1.748	0.05545	0.001179	415	0.98	0.01	0.51	0.04	108	504	687	720	b	0.7	104
J025939.0+140253	44.9125	14.04806	10	0.05784	0.01322	0.000978	442	0.98	0.14	0.44	0.19	0	null	44	300	b	0.73	11
J031110.0+142418	47.79167	14.405	22	0.06012	0.01762	0.001001	259	1	0.23	0.84	0.3	0	null	20	300	b	0.67	6
J030443.2+143740	46.18	14.62792	11	0.1941	0.03089	0.001002	230	0.59	0.13	-0.14	0.17	18	2	108	300	b	0.75	10
J025225.6+125231	43.10667	12.87542	15	0.06661	0.01713	0.00085	271	1	0.13	0.21	0.23	0	null	32	300	b	0.74	7
J025125.7+132309	42.85708	13.38583	10	0.2248	0.03104	0.000878	279	-0.23	0.14	-0.1	0.23	9	1	118	300	b	0.72	8
J024817.2+132226	42.07167	13.37403	29	0.08694	0.02076	0.00085	254	1	0.12	0.77	0.15	0	null	33	300	b	0.7	15
J025437.1+152558	43.65458	15.43292	12	0.06979	0.01587	0.000957	361	0.91	0.16	-0.1	0.23	0	null	37	300	b	0.74	7
J025351.3+152118	43.46375	15.355	9	0.2918	0.03104	0.000896	354	-0.03	0.1	0	0.14	19	7	222	300	b	0.73	8
J024524.3+143518	41.35125	14.58847	10	0.1827	0.02991	0.000839	257	0.61	0.14	0.31	0.15	8	1	104	300	b	0.7	13
J024807.8+150010	42.0325	15.00278	12	0.05108	0.01512	0.000751	307	0.49	0.3	-0.5	0.5	0	null	24	300	b	0.7	5
J030007.6+163023	45.03167	16.50653	7	0.3292	0.02993	0.000908	396	0.91	0.04	0.32	0.08	0	null	358	300	b	0.7	8
J025038.8+171215	42.66167	17.20417	10	0.1169	0.02019	0.000828	348	1	0.07	0.23	0.16	0	null	84	300	b	0.7	5
J025626.2+180111	44.10917	18.01986	17	0.05151	0.01292	0.000852	439	-0.36	0.23	0.53	0.43	23	2	25	300	b	0.76	10
J034314.1+102941	55.80875	10.49486	9	0.2101	0.02751	0.000723	359	-0.95	0.06	-0.01	0.77	0	null	138	300	b	0.76	1
J034926.6+110837	57.36084	11.14375	10	0.3388	0.03236	0.000697	372	0.57	0.08	0.14	0.1	29	4	313	300	b	0.71	8
J035024.5+130424	57.60209	13.07347	10	0.06953	0.01497	0.000592	365	0.55	0.2	0.36	0.22	0	null	57	300	b	0.75	5
J034231.8+121622	55.6325	12.27292	12	0.07307	0.01603	0.00075	365	-0.06	0.21	0.85	0.38	13	2	43	300	b	0.74	5
J034019.2+122029	55.08	12.34139	12	0.06205	0.01419	0.000745	367	0.83	0.15	-0.11	0.24	0	null	47	300	b	0.75	5
J034328.1+132529	55.86708	13.42472	11	0.07616	0.01547	0.000703	369	0.87	0.14	0.54	0.17	0	null	64	300	b	0.74	1
J040054.8+150946	60.22833	15.16292	16	0.06415	0.01536	0.000566	331	1	0.18	0.33	0.21	0	null	44	300	b	0.69	3
J035101.5+141404	57.75625	14.23458	11	0.1487	0.02231	0.000628	367	-0.35	0.13	0.02	0.25	0	null	102	300	b	0.74	4
J035205.4+142953	58.0225	14.49819	10	0.05648	0.01445	0.000603	334	0.67	0.25	0.38	0.24	0	null	43	300	b	0.73	5
J035139.0+144753	57.9125	14.79819	12	0.05879	0.01405	0.000618	349	1	0.19	0.26	0.22	14	2	45	300	b	0.75	5
J035126.3+152143	57.85958	15.36194	12	0.05902	0.0144	0.000626	345	1	0.16	0.39	0.21	8	1	43	300	b	0.71	5
J035453.6+161912	58.72333	16.32014	10	0.1091	0.02058	0.000573	327	-0.2	0.16	0.01	0.26	0	null	65	300	b	0.75	3
J032548.2+135347	51.45084	13.89639	10	0.06428	0.01347	0.000837	447	1	0.07	0.68	0.15	9	1	64	300	b	0.73	5
J034118.9+152423	55.32875	15.40639	19	0.4577	0.03282	0.000712	364	1	0.04	0.7	0.1	113	105	111	585	b	0.7	16
J035028.0+163121	57.61667	16.5225	10	0.07544	0.01632	0.000655	330	0.95	0.13	0.24	0.21	10	1	68	300	b	0.78	6
J035428.3+163659	58.61792	16.61639	11	0.057	0.01535	0.000568	330	-0.38	0.25	-0.77	0.56	0	null	32	300	b	0.72	9
J035309.6+171943	58.29	17.32875	12	0.0561	0.01499	0.000615	328	-0.25	0.23	0.33	1.17	0	null	30	300	b	0.74	9
J034613.8+170929	56.5575	17.15806	10	0.1857	0.0251	0.000597	338	0.16	0.13	-0.01	0.17	0	null	139	300	b	0.71	7
J035025.0+171455	57.60417	17.24875	7	1.553	0.0686	0.000679	339	-0.71	0.03	0.06	0.11	17	15	1,700	300	b	0.75	11
J035116.3+174304	57.81792	17.71792	17	0.05148	0.01429	0.000672	343	0.5	0.27	0.35	0.28	11	1	28	300	b	0.72	10
J034234.3+173807	55.64292	17.63528	15	0.0576	0.01511	0.000665	347	0.99	0.21	-0.09	0.25	0	null	25	300	b	0.71	13
J034526.5+174702	56.36042	17.78403	10	0.1628	0.02375	0.000621	348	0.3	0.14	-0.03	0.17	20	4	123	300	b	0.75	7
J034308.0+185836	55.78334	18.9768	12	0.1826	0.02243	0.000628	367	0.99	0.07	0.42	0.11	25	5	165	300	b	0.69	5
J041738.4+165659	64.41	16.94972	10	0.2369	0.02557	0.000903	415	0	0.1	0.42	0.13	0	null	198	300	b	0.71	18
J040321.7+171646	60.84042	17.27958	11	0.09301	0.01953	0.000672	279	0.73	0.16	0.6	0.18	0	null	59	300	b	0.72	3
J035845.9+162716	59.69125	16.45458	13	0.0571	0.01389	0.000593	340	1	0.09	0.56	0.19	0	null	45	300	b	0.75	5
J040513.2+173647	61.305	17.61306	10	0.0972	0.02143	0.000657	241	1	0.12	0.59	0.19	0	null	62	300	b	0.73	2
J040753.6+175032	61.97334	17.84236	13	0.1119	0.0219	0.00073	276	0.28	0.18	-0.14	0.24	20	3	53	300	b	0.75	3
J041042.4+182519	62.67667	18.42194	13	0.05774	0.01561	0.000766	339	-0.26	0.23	-0.64	0.47	0	null	29	300	b	0.72	7
J041851.4+172335	64.71416	17.39319	11	0.06898	0.01492	0.000885	407	0.21	0.21	-0.4	0.25	0	null	46	300	b	0.74	8

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ROSAT All-Sky Survey Bright Source Catalog

All-sky X-ray map from ROSAT survey showing the hot universe

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, 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

Column	Type	Description	Sample	Null %
`iau_name`	str	IAU source designation in format 1RXS JHHMMSS.s+DDMMSS	J030145.1+011538	0.0%
`note_flag`	str	Note flag: 'N' = new source added post-publication		0.0%
`ra_deg`	float64	Right ascension (J2000, degrees)	45.43792	0.0%
`dec_deg`	float64	Declination (J2000, degrees)	1.26056	0.0%
`pos_error_arcsec`	float64	90% confidence positional error radius (arcsec); typical ~30 arcsec	13.0	0.3%
`count_rate`	float64	ROSAT PSPC source count rate in the 0.1–2.4 keV band (counts/s)	0.1039	0.0%
`count_rate_err`	float64	1-sigma error on count_rate (counts/s)	0.02598	0.3%
`bg_count_rate`	float64	Background count rate per arcmin² at source position (counts/s/arcmin²)	0.000957	0.3%
`exp_time_s`	float64	Effective ROSAT PSPC exposure time at source position (seconds)	181.0	0.0%
`hardness_ratio_1`	float64	Hardness ratio HR1 = (B-A)/(B+A), where A=0.1–0.4 keV, B=0.5–2.0 keV	0.44	0.0%
`hardness_ratio_1_err`	float64	1-sigma error on hardness_ratio_1	0.23	0.0%
`hardness_ratio_2`	float64	Hardness ratio HR2 = (D-C)/(D+C), where C=0.5–0.9 keV, D=0.9–2.0 keV	0.08	0.0%
`hardness_ratio_2_err`	float64	1-sigma error on hardness_ratio_2	0.27	0.0%
`source_extent`	int64	Source extent (arcsec) from RASS profile fitting; 0 = point source	10	0.0%
`extent_likelihood`	float64	Likelihood of source being extended; >10 suggests extent	1.0	44.0%
`detection_likelihood`	float64	Maximum likelihood of source detection; threshold ~15 for BSC	40.0	0.3%
`extent_radius_arcsec`	int64	Radius used for source photon extraction (arcsec)	300	0.0%
`spectral_band`	str	Hardness-based spectral band classification (a–e, hard to soft)	b	0.0%
`vignetting_factor`	float64	Effective exposure correction for off-axis vignetting (0–1)	0.78	0.3%
`num_candidates`	int64	Number of source candidates in the detection cell	11	0.0%

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

Related datasets

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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 = {juliensimon},
  year = {2026},
  url = {https://huggingface.co/datasets/juliensimon/rosat-bright-source-catalog},
  publisher = {Hugging Face}
}