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Home > Einstein Probe follow up > EP250827a

EP_FIELD00062

EP

62

/EP

EP250827a: Swift observation summary

Data analysed so far:

• ObsID: 03000043001 with 1.6 ks exposure.
• ObsID: 03000043002 with 2.7 ks exposure.
• ObsID: 03000043003 with 2.9 ks exposure.

About tiled field analysis.

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

• 3000043 — 7.1 ks of cleaned data taken between 2025-08-27 08:32:04 and 2025-08-28 19:08:07

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]	00h 13m 52.17s3.46738°	-56° 29′ 51.3″-56.49757°	2.7′′ *	Good	1 (T)	2.2′	10.0 ks	The source is fading with 4.4-σ significance.
Mean XRT rate: 3.70 (±0.24) ×10-2 ct s-1 Peak XRT rate: 0.25 (±0.06) ct s-1 RASS PSPC 3-σ upper limit: 0.19 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.084 (±0.005) ct s-1 Peak XRT rate converted to PSPC: 0.57 (±0.13) ct s-1 Mean XRT flux: 1.29 (±0.08) ×10-12 erg cm-1s-1 Peak XRT flux: 8.8 (±2.0) ×10-12 erg cm-1s-1 Products: Light curve | Spectrum | Enhanced position

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 15 sources have been found in the XRT data. 1 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err901	Detection Flag2	Rank3	Dist from Einstein Probe/WXT pos	Exposure	Notes	Vizier
1 [details]	00h 13m 52.17s3.46738°	-56° 29′ 51.3″-56.49757°	2.7′′ *	Good	1 (T)	2.2′	10.0 ks	The source is fading with 4.4-σ significance.
Mean XRT rate: 3.70 (±0.24) ×10-2 ct s-1 Peak XRT rate: 0.25 (±0.06) ct s-1 RASS PSPC 3-σ upper limit: 0.19 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.084 (±0.005) ct s-1 Peak XRT rate converted to PSPC: 0.57 (±0.13) ct s-1 Mean XRT flux: 1.29 (±0.08) ×10-12 erg cm-1s-1 Peak XRT flux: 8.8 (±2.0) ×10-12 erg cm-1s-1 Products: Light curve | Spectrum | Enhanced position
2 [details]	00h 12m 46.77s3.19489°	-56° 24′ 15.1″-56.40419°	6.1′′	Good	3 (U)	10.3′	10.0 ks
Mean XRT rate: 1.4 (+0.6, -0.5) ×10-3 ct s-1 Peak XRT rate: 1.4 (+0.6, -0.5) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.18 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 3.2 (+1.3, -1.1) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 3.2 (+1.3, -1.1) ×10-3 ct s-1 Mean XRT flux: 7.0 (+2.9, -2.3) ×10-14 erg cm-1s-1 Peak XRT flux: 7.0 (+2.9, -2.3) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
3 [details]	00h 12m 49.11s3.20464°	-56° 28′ 23.6″-56.47322°	7.7′′	Reasonable	3 (U)	9.4′	10.0 ks
Mean XRT rate: 2.9 (+0.9, -0.8) ×10-3 ct s-1 Peak XRT rate: 2.9 (+0.9, -0.8) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.28 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 3.76 (+1.19, -0.99) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 3.76 (+1.19, -0.99) ×10-3 ct s-1 Mean XRT flux: 8.7 (+2.7, -2.3) ×10-14 erg cm-1s-1 Peak XRT flux: 8.7 (+2.7, -2.3) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
4 [details]	00h 15m 05.38s3.77240°	-56° 27′ 47.7″-56.46326°	4.7′′ *	Good	3 (U)	9.4′	10.0 ks
Mean XRT rate: 1.4 (+0.6, -0.5) ×10-3 ct s-1 Peak XRT rate: 1.4 (+0.6, -0.5) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.01 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.021 (+0.009, -0.007) ×10-2 ct s-1 Peak XRT rate converted to PSPC: 0.021 (+0.009, -0.007) ×10-2 ct s-1 Mean XRT flux: 4.0 (+1.7, -1.3) ×10-14 erg cm-1s-1 Peak XRT flux: 4.0 (+1.7, -1.3) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum | Enhanced position
5 [details]	00h 14m 05.62s3.52344°	-56° 22′ 44.6″-56.37907°	8.5′′	Reasonable	3 (U)	5.2′	10.0 ks
Mean XRT rate: 1.4 (+0.6, -0.5) ×10-3 ct s-1 Peak XRT rate: 1.4 (+0.6, -0.5) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.10 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 2.9 (+1.3, -1.0) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 2.9 (+1.3, -1.0) ×10-3 ct s-1 Mean XRT flux: 2.2 (+1.0, -0.8) ×10-14 erg cm-1s-1 Peak XRT flux: 2.2 (+1.0, -0.8) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
6 [details]	00h 13m 52.84s3.47018°	-56° 28′ 00.6″-56.46683°	6.2′′	Poor	3 (U)	0.6′	10.0 ks
Mean XRT rate: 1.7 (+0.6, -0.5) ×10-3 ct s-1 Peak XRT rate: 1.7 (+0.6, -0.5) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.09 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 4.3 (+1.5, -1.3) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 4.3 (+1.5, -1.3) ×10-3 ct s-1 Mean XRT flux: 5.8 (+2.1, -1.7) ×10-14 erg cm-1s-1 Peak XRT flux: 5.8 (+2.1, -1.7) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
7 [details]	00h 12m 50.47s3.21028°	-56° 26′ 20.7″-56.43909°	8.9′′	Poor	3 (U)	9.3′	10.0 ks
Mean XRT rate: 7 (+5, -3) ×10-4 ct s-1 Peak XRT rate: 7 (+5, -3) ×10-4 ct s-1 RASS PSPC 3-σ upper limit: 0.19 ct s-1 (PSPC count-rate) Products: Light curve | Spectrum
8 [details]	00h 14m 07.03s3.52931°	-56° 40′ 51.7″-56.68103°	7.1′′	Poor	3 (U)	13.2′	8.4 ks
Mean XRT rate: 2.5 (+0.9, -0.7) ×10-3 ct s-1 Peak XRT rate: 2.5 (+0.9, -0.7) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.17 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 3.33 (+1.14, -0.94) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 3.33 (+1.14, -0.94) ×10-3 ct s-1 Mean XRT flux: 1.3 (+0.5, -0.4) ×10-13 erg cm-1s-1 Peak XRT flux: 1.3 (+0.5, -0.4) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum
9 [details]	00h 14m 02.45s3.51019°	-56° 30′ 05.7″-56.50158°	5.5′′	Good	3 (U)	2.4′	10.0 ks
Mean XRT rate: 1.5 (+0.6, -0.5) ×10-3 ct s-1 Peak XRT rate: 1.5 (+0.6, -0.5) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.18 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 2.5 (+0.9, -0.8) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 2.5 (+0.9, -0.8) ×10-3 ct s-1 Mean XRT flux: 7.2 (+2.7, -2.2) ×10-14 erg cm-1s-1 Peak XRT flux: 7.2 (+2.7, -2.2) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
10 [details]	00h 12m 55.31s3.23047°	-56° 32′ 28.0″-56.54111°	7.4′′	Good	3 (U)	9.7′	10.0 ks
Mean XRT rate: 1.5 (+0.6, -0.5) ×10-3 ct s-1 Peak XRT rate: 1.5 (+0.6, -0.5) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.14 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 3.3 (+1.4, -1.1) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 3.3 (+1.4, -1.1) ×10-3 ct s-1 Mean XRT flux: 4.9 (+2.1, -1.7) ×10-14 erg cm-1s-1 Peak XRT flux: 4.9 (+2.1, -1.7) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
11 [details]	00h 14m 26.85s3.61188°	-56° 38′ 24.5″-56.64015°	8.1′′	Good	3 (U)	11.4′	10.0 ks	Matches SIMBAD source: AT20G J001427-563822, 1.9″ away.
Mean XRT rate: 1.4 (+0.6, -0.5) ×10-3 ct s-1 Peak XRT rate: 1.4 (+0.6, -0.5) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.10 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 2.9 (+1.3, -1.0) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 2.9 (+1.3, -1.0) ×10-3 ct s-1 Mean XRT flux: 3.9 (+1.7, -1.4) ×10-14 erg cm-1s-1 Peak XRT flux: 3.9 (+1.7, -1.4) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
12 [details]	00h 13m 09.77s3.29069°	-56° 32′ 23.6″-56.53988°	5.2′′	Good	3 (U)	8.0′	10.0 ks
Mean XRT rate: 1.9 (+0.7, -0.6) ×10-3 ct s-1 Peak XRT rate: 1.9 (+0.7, -0.6) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.38 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 1.6 (+0.6, -0.5) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 1.6 (+0.6, -0.5) ×10-3 ct s-1 Mean XRT flux: 1.3 (+0.5, -0.4) ×10-13 erg cm-1s-1 Peak XRT flux: 1.3 (+0.5, -0.4) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum
13 [details]	00h 13m 51.58s3.46491°	-56° 37′ 53.6″-56.63157°	8.1′′	Reasonable	3 (U)	10.1′	10.0 ks
Mean XRT rate: 2.1 (±0.6) ×10-3 ct s-1 Peak XRT rate: 2.1 (±0.6) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.21 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 4.2 (±1.2) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 4.2 (±1.2) ×10-3 ct s-1 Mean XRT flux: 7.4 (±2.1) ×10-14 erg cm-1s-1 Peak XRT flux: 7.4 (±2.1) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
14 [details]	00h 14m 35.10s3.64625°	-56° 32′ 35.4″-56.54318°	6.7′′	Poor	3 (U)	7.1′	10.0 ks
Mean XRT rate: 10 (+5, -4) ×10-4 ct s-1 Peak XRT rate: 10 (+5, -4) ×10-4 ct s-1 RASS PSPC 3-σ upper limit: 0.18 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 1.4 (+0.7, -0.6) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 1.4 (+0.7, -0.6) ×10-3 ct s-1 Mean XRT flux: 2.9 (+1.5, -1.2) ×10-14 erg cm-1s-1 Peak XRT flux: 2.9 (+1.5, -1.2) ×10-14 erg cm-1s-1 Products: Light curve | Spectrum
15 [details]	00h 14m 35.84s3.64932°	-56° 35′ 23.3″-56.58980°	6.9′′	Poor	3 (U)	9.3′	10.0 ks
Mean XRT rate: undetermined ct s-1 Peak XRT rate: undetermined ct s-1 RASS PSPC 3-σ upper limit: 1.3×10-10 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: undetermined ct s-1 Peak XRT rate converted to PSPC: undetermined ct s-1 Mean XRT flux: undetermined erg cm-1s-1 Peak XRT flux: undetermined 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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FITS exposure map.