sb25081303: Swift observation summary

This is a confirmed GRB (GRB 250813B), the afterglow is source 1 -- please see the GRB results at https://www.swift.ac.uk/xrt_products/03000025 for updated analysis

Mission:	SVOM/ECLAIRs
SVOM RA:	336.728°
SVOM Dec:	+12.498°
SVOM Err:	2.2 arcmin
T0:	2025-08-13 22:51:15 UT
Galactic:	76.74° -37.09°
Galactic N_H:	4.85× 10²⁰ cm^-2

Sun distance:	150.00°
Sun angle:	11.12 [hr] (West of Sun)
Moon distance:	40.76°
Visibility of this field.
First slew:	2025-08-14 01:28:32 UT
First observation:	2025-08-14 01:27:56 UT
First analysis:	2025-08-14 09:39:57 UT

Data analysed so far:

ObsID: 03000025001 with 1.6 ks exposure.

About tiled field analysis.

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

3000025 — 1.6 ks of cleaned data taken between 2025-08-14 01:28:25 and 2025-08-14 03:22:59

Details of afterglow candidates

1 sources were found which matches the afterglow criteria.

#	RA (J2000)	Dec (J2000)	Err₉₀¹	Detection Flag²	Rank³	Dist from SVOM/ECLAIRs pos	Exposure	Notes	Vizier
1 [details]	22h 27m 00.19s336.75081°	+12° 27′ 44.2″12.46227°	2.8′′ ^*	Good	1 (T)	2.5′	1.6 ks	The source is 4.0-σ above the RASS limit.
Mean XRT rate: 0.177 (±0.013) ct s^-1 Peak XRT rate: 0.27 (±0.06) ct s^-1 RASS PSPC 3-σ upper limit: 0.02 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.227 (±0.016) ct s^-1 Peak XRT rate converted to PSPC: 0.34 (±0.08) ct s^-1 Mean XRT flux: 6.1 (±0.4) ×10^-12 erg cm^-1s^-1 Peak XRT flux: 9.2 (±2.1) ×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 4 sources have been found in the XRT data. 2 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err₉₀¹	Detection Flag²	Rank³	Dist from SVOM/ECLAIRs pos	Exposure	Notes
1 [details]	22h 27m 00.19s336.75081°	+12° 27′ 44.2″12.46227°	2.8′′ ^*	Good	1 (T)	2.5′	1.6 ks	The source is 4.0-σ above the RASS limit.
Mean XRT rate: 0.177 (±0.013) ct s^-1 Peak XRT rate: 0.27 (±0.06) ct s^-1 RASS PSPC 3-σ upper limit: 0.02 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.227 (±0.016) ct s^-1 Peak XRT rate converted to PSPC: 0.34 (±0.08) ct s^-1 Mean XRT flux: 6.1 (±0.4) ×10^-12 erg cm^-1s^-1 Peak XRT flux: 9.2 (±2.1) ×10^-12 erg cm^-1s^-1 Products: Light curve \| Spectrum \| Enhanced position
2 [details]	22h 26m 29.94s336.62473°	+12° 27′ 06.7″12.45185°	5.2′′	Good	3 (U)	6.7′	1.6 ks	Matches SIMBAD source: NVSS J222630+122709, 6.5″ away.
Mean XRT rate: 5.8 (+2.7, -2.1) ×10^-3 ct s^-1 Peak XRT rate: 5.8 (+2.7, -2.1) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.03 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 8.2 (+3.8, -3.0) ×10^-3 ct s^-1 Peak XRT rate converted to PSPC: 8.2 (+3.8, -3.0) ×10^-3 ct s^-1 Mean XRT flux: 2.0 (+0.9, -0.7) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 2.0 (+0.9, -0.7) ×10^-13 erg cm^-1s^-1 Products: Light curve \| Spectrum
3 [details]	22h 26m 48.67s336.70281°	+12° 23′ 59.2″12.39977°	7.1′′	Reasonable	3 (U)	6.1′	1.6 ks
Mean XRT rate: 3.5 (+2.4, -1.7) ×10^-3 ct s^-1 Peak XRT rate: 3.5 (+2.4, -1.7) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.03 ct s^-1 (PSPC count-rate) Products: Light curve \| Spectrum
4 [details]	22h 27m 14.80s336.81165°	+12° 32′ 13.1″12.53698°	6.3′′	Poor	3 (U)	5.4′	1.6 ks	Matches SIMBAD source: SDSS J222714.98+123216.0, 4″ away.
Mean XRT rate: 3.8 (+2.5, -1.7) ×10^-3 ct s^-1 Peak XRT rate: 3.8 (+2.5, -1.7) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.03 ct s^-1 (PSPC count-rate) Products: Light curve \| Spectrum

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FITS exposure map.