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Home > Einstein Probe follow up > EP250812a

EP_FIELD00058

EP

58

/EP

EP250812a: Swift observation summary

Data analysed so far:

• ObsID: 00019995001 with 2.0 ks exposure.

About tiled field analysis.

So far 1 fields have been scheduled for observations. Data are available and processed for 1 of these.

• 19995 — 2.0 ks of cleaned data taken between 2025-08-12 13:34:43 and 2025-08-12 15:14:39

Details of afterglow candidates

1 sources were found which matches the afterglow criteria.

#	RA (J2000)	Dec (J2000)	Err901	Detection Flag2	Rank3	Dist from Einstein Probe/WXT pos	Exposure	Notes	Vizier
1 [details]	02h 03m 58.10s30.99209°	-09° 19′ 07.5″-9.31875°	3.7′′	Good	1 (T)	1.1′	2.0 ks	The source is fading with 3.1-σ significance. The source is 4.4-σ above the LSPXS limit.
Mean XRT rate: 0.101 (±0.008) ct s-1 Peak XRT rate: 0.21 (±0.05) ct s-1 RASS PSPC 3-σ upper limit: 0.02 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.139 (±0.011) ct s-1 Peak XRT rate converted to PSPC: 0.29 (±0.06) ct s-1 Mean XRT flux: 3.53 (±0.28) ×10-12 erg cm-1s-1 Peak XRT flux: 7.2 (±1.6) ×10-12 erg cm-1s-1 Products: Light curve | Spectrum

¹ Radius, 90% confidence.
² Indicates how likely the source is to be real. See the LSXPS documentation.
³ T=Transient Source, O=Outbursting known source, U=Uncatalogued X-ray source, K=Known X-ray source.
^* The position was enhanced using astrometry derived from the Swift UVOT.
^† The position was astrometrically corrected using the XRT sources and the 2MASS catalogue.

Find an upper limit.

Sources found so far

So far 6 sources have been found in the XRT data. 5 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err901	Detection Flag2	Rank3	Dist from Einstein Probe/WXT pos	Exposure	Notes	Vizier
1 [details]	02h 03m 58.10s30.99209°	-09° 19′ 07.5″-9.31875°	3.7′′	Good	1 (T)	1.1′	2.0 ks	The source is fading with 3.1-σ significance. The source is 4.4-σ above the LSPXS limit.
Mean XRT rate: 0.101 (±0.008) ct s-1 Peak XRT rate: 0.21 (±0.05) ct s-1 RASS PSPC 3-σ upper limit: 0.02 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.139 (±0.011) ct s-1 Peak XRT rate converted to PSPC: 0.29 (±0.06) ct s-1 Mean XRT flux: 3.53 (±0.28) ×10-12 erg cm-1s-1 Peak XRT flux: 7.2 (±1.6) ×10-12 erg cm-1s-1 Products: Light curve | Spectrum
2 [details]	02h 03m 40.71s30.91964°	-09° 21′ 34.6″-9.35960°	5.8′′	Good	4 (K)	4.8′	2.0 ks	Matches SIMBAD source: [VV2006] J020341.0-092134, 3.4″ away. Matches known X-ray source: LSXPS J020340.7-092134 (from LSXPS), 1″ away.
Mean XRT rate: 9.4 (+2.9, -2.4) ×10-3 ct s-1 Peak XRT rate: 9.4 (+2.9, -2.4) ×10-3 ct s-1 -1.70 σ above the catalogued flux from LSXPS. RASS PSPC 3-σ upper limit: 0.0×100 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.020 (+0.006, -0.005) ×10-2 ct s-1 Peak XRT rate converted to PSPC: 0.020 (+0.006, -0.005) ×10-2 ct s-1 Mean XRT flux: 2.7 (+0.9, -0.7) ×10-13 erg cm-1s-1 Peak XRT flux: 2.7 (+0.9, -0.7) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum
3 [details]	02h 03m 29.46s30.87277°	-09° 10′ 23.1″-9.17308°	7.2′′ *	Good	3 (U)	10.1′	2.0 ks	Matches SIMBAD source: QSO J0203-0910, 7.3″ away.
Mean XRT rate: 6.7 (+2.7, -2.1) ×10-3 ct s-1 Peak XRT rate: 6.7 (+2.7, -2.1) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.04 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 10 (+4, -3) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 10 (+4, -3) ×10-3 ct s-1 Mean XRT flux: 3.2 (+1.3, -1.0) ×10-13 erg cm-1s-1 Peak XRT flux: 3.2 (+1.3, -1.0) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum | Enhanced position
4 [details]	02h 04m 04.78s31.01990°	-09° 15′ 04.8″-9.25133°	5.8′′	Good	4 (K)	4.0′	2.0 ks	Matches known X-ray source: LSXPS J020405.1-091509 (from LSXPS), 7.3″ away.
Mean XRT rate: 6.3 (+2.5, -2.0) ×10-3 ct s-1 Peak XRT rate: 6.3 (+2.5, -2.0) ×10-3 ct s-1 -0.27 σ above the catalogued flux from LSXPS. RASS PSPC 3-σ upper limit: 0.0×100 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.010 (+0.004, -0.003) ×10-2 ct s-1 Peak XRT rate converted to PSPC: 0.010 (+0.004, -0.003) ×10-2 ct s-1 Mean XRT flux: 2.3 (+0.9, -0.7) ×10-13 erg cm-1s-1 Peak XRT flux: 2.3 (+0.9, -0.7) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum
5 [details]	02h 03m 22.45s30.84355°	-09° 21′ 24.2″-9.35672°	6.4′′	Reasonable	4 (K)	8.6′	2.0 ks	Matches known X-ray source: LSXPS J020322.7-092131 (from LSXPS), 8.5″ away.
Mean XRT rate: 3.8 (+2.2, -1.6) ×10-3 ct s-1 Peak XRT rate: 3.8 (+2.2, -1.6) ×10-3 ct s-1 0.29 σ below the catalogued flux from LSXPS. RASS PSPC 3-σ upper limit: 0.0×100 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 7 (+4, -3) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 7 (+4, -3) ×10-3 ct s-1 Mean XRT flux: 1.1 (+0.6, -0.5) ×10-13 erg cm-1s-1 Peak XRT flux: 1.1 (+0.6, -0.5) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum
6 [details]	02h 04m 17.66s31.07357°	-09° 16′ 52.4″-9.28122°	6.1′′	Good	4 (K)	5.8′	2.0 ks	Matches known X-ray source: LSXPS J020417.7-091657 (from LSXPS), 5.3″ away.
Mean XRT rate: 4.3 (+2.2, -1.7) ×10-3 ct s-1 Peak XRT rate: 4.3 (+2.2, -1.7) ×10-3 ct s-1 1.12 σ below the catalogued flux from LSXPS. RASS PSPC 3-σ upper limit: 0.0×100 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 3.0 (+1.5, -1.2) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 3.0 (+1.5, -1.2) ×10-3 ct s-1 Mean XRT flux: 4.1 (+2.1, -1.6) ×10-13 erg cm-1s-1 Peak XRT flux: 4.1 (+2.1, -1.6) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum

¹ Radius, 90% confidence.
² Indicates how likely the source is to be real. See the LSXPS documentation.
³ T=Transient Source, O=Outbursting known source, U=Uncatalogued X-ray source, K=Known X-ray source.
^* The position was enhanced using astrometry derived from the Swift UVOT.
^† The position was astrometrically corrected using the XRT sources and the 2MASS catalogue.

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Exposure map

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FITS exposure map.