GRB 260204A: Swift observation summary

This is a confirmed GRB (GRB 260204A), the afterglow is source 1 -- please see the GRB results at https://www.swift.ac.uk/xrt_products/03000405 for updated analysis

Mission:	SVOM/ECLAIRs
SVOM RA:	205.119°
SVOM Dec:	+2.020°
SVOM Err:	7.4 arcmin
T0:	2026-02-04 14:48:28 UT
Galactic:	330.07° +62.28°
Galactic N_H:	1.75× 10²⁰ cm^-2

Sun distance:	112.42°
Sun angle:	7.52 [hr](West of Sun)
Moon distance:	35.16°
Visibility of this field.
First slew:	2026-02-04 21:25:39 UT
First observation:	2026-02-04 21:17:03 UT
First analysis:	2026-02-04 23:37:01 UT

Data analysed so far:

ObsID: 03000405001 with 1.7 ks exposure.

About tiled field analysis.

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

3000405 — 1.7 ks of cleaned data taken between 2026-02-04 21:18:03 and 2026-02-04 21:50:06

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]	13h 40m 25.50s205.10623°	+01° 55′ 50.7″1.93075°	4.2′′ ^*	Good	2 (O)	5.4′	4.3 ks	The source is fading with 4.6-σ significance.
Mean XRT rate: 2.4 (±0.5) ×10^-2 ct s^-1 Peak XRT rate: 2.4 (±0.5) ×10^-2 ct s^-1 RASS PSPC 3-σ upper limit: 0.04 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.041 (±0.008) ct s^-1 Peak XRT rate converted to PSPC: 0.041 (±0.008) ×10^-2 ct s^-1 Mean XRT flux: 9.2 (±1.8) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 9.2 (±1.8) ×10^-13 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. 3 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err₉₀¹	Detection Flag²	Rank³	Dist from SVOM/ECLAIRs pos	Exposure	Notes
1 [details]	13h 40m 25.50s205.10623°	+01° 55′ 50.7″1.93075°	4.2′′ ^*	Good	2 (O)	5.4′	4.3 ks	The source is fading with 4.6-σ significance.
Mean XRT rate: 2.4 (±0.5) ×10^-2 ct s^-1 Peak XRT rate: 2.4 (±0.5) ×10^-2 ct s^-1 RASS PSPC 3-σ upper limit: 0.04 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.041 (±0.008) ct s^-1 Peak XRT rate converted to PSPC: 0.041 (±0.008) ×10^-2 ct s^-1 Mean XRT flux: 9.2 (±1.8) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 9.2 (±1.8) ×10^-13 erg cm^-1s^-1 Products: Light curve \| Spectrum \| Enhanced position
2 [details]	13h 40m 26.97s205.11239°	+02° 09′ 01.3″2.15035°	3.8′′ ^*	Good	3 (U)	7.8′	2.3 ks	Matches SIMBAD source: HD 118981, 0.7″ away.
Mean XRT rate: 1.5 (±0.3) ×10^-2 ct s^-1 Peak XRT rate: 1.7 (+0.8, -0.6) ×10^-2 ct s^-1 RASS PSPC 3-σ upper limit: 0.03 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.030 (+0.007, -0.006) ct s^-1 Peak XRT rate converted to PSPC: 0.035 (+0.016, -0.012) ×10^-2 ct s^-1 Mean XRT flux: 2.4 (+0.6, -0.5) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 2.77 (+1.32, -1.00) ×10^-13 erg cm^-1s^-1 Products: Light curve \| Spectrum \| Enhanced position
3 [details]	13h 40m 23.65s205.09853°	+01° 56′ 10.5″1.93625°	5.8′′ ^*	Good	4 (K)	5.2′	4.3 ks	This source may be affected by optical loading Matches known X-ray source: XMMSL3 J134023.8+015613 (from XMM-NEWTON/XMMSLEWCLN), 1.5517922236173″ away.
Mean XRT rate: 1.22 (+0.26, -0.25) ×10^-2 ct s^-1 Peak XRT rate: 2.3 (±0.6) ×10^-2 ct s^-1 1.54 σ below the catalogued flux from XMM-NEWTON/XMMSLEWCLN. RASS PSPC 3-σ upper limit: 0.0×10⁰ ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.021 (+0.005, -0.004) ct s^-1 Peak XRT rate converted to PSPC: 0.039 (±0.010) ×10^-2 ct s^-1 Mean XRT flux: 2.6 (±0.5) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 4.8 (±1.2) ×10^-13 erg cm^-1s^-1 Products: Light curve \| Spectrum \| Enhanced position
4 [details]	13h 40m 43.07s205.17945°	+02° 03′ 08.7″2.05243°	6.1′′ ^*	Good	3 (U)	4.1′	4.3 ks	Matches SIMBAD source: [VV2006] J134042.9+020307, 4.5″ away.
Mean XRT rate: 5.1 (+1.6, -1.3) ×10^-3 ct s^-1 Peak XRT rate: 7.2 (+2.9, -2.3) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.02 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 9.1 (+2.9, -2.2) ×10^-3 ct s^-1 Peak XRT rate converted to PSPC: 0.013 (+0.005, -0.004) ×10^-2 ct s^-1 Mean XRT flux: 1.18 (+0.37, -0.29) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 1.7 (+0.7, -0.5) ×10^-13 erg cm^-1s^-1 Products: Light curve \| Spectrum \| Enhanced position

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Exposure map

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FITS exposure map.