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Home > SVOM follow up > GRB 250903A

SVOM_FIELD00034

SVOM

34

/SVOM

GRB 250903A: Swift observation summary

This is a confirmed GRB (GRB 250903A), the afterglow is source 1 -- please see the GRB results at https://www.swift.ac.uk/xrt_products/03000070 for updated analysis

Data analysed so far:

• ObsID: 03000070001 with 2.4 ks exposure.

About tiled field analysis.

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

• 3000070 — 2.4 ks of cleaned data taken between 2025-09-03 20:54:55 and 2025-09-04 00:18:39

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]	23h 47m 12.18s356.80076°	-75° 57′ 57.6″-75.96601°	4.3′′	Good	2 (O)	2.7′	6.3 ks	The source is fading with 3.8-σ significance.
Mean XRT rate: 3.9 (±0.5) ×10-2 ct s-1 Peak XRT rate: 5.2 (±1.4) ×10-2 ct s-1 RASS PSPC 3-σ upper limit: 0.09 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.062 (±0.008) ct s-1 Peak XRT rate converted to PSPC: 0.084 (±0.022) ×10-2 ct s-1 Mean XRT flux: 1.26 (±0.16) ×10-12 erg cm-1s-1 Peak XRT flux: 1.7 (±0.4) ×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 4 sources have been found in the XRT data. 1 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err901	Detection Flag2	Rank3	Dist from SVOM/ECLAIRs pos	Exposure	Notes	Vizier
1 [details]	23h 47m 12.18s356.80076°	-75° 57′ 57.6″-75.96601°	4.3′′	Good	2 (O)	2.7′	6.3 ks	The source is fading with 3.8-σ significance.
Mean XRT rate: 3.9 (±0.5) ×10-2 ct s-1 Peak XRT rate: 5.2 (±1.4) ×10-2 ct s-1 RASS PSPC 3-σ upper limit: 0.09 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.062 (±0.008) ct s-1 Peak XRT rate converted to PSPC: 0.084 (±0.022) ×10-2 ct s-1 Mean XRT flux: 1.26 (±0.16) ×10-12 erg cm-1s-1 Peak XRT flux: 1.7 (±0.4) ×10-12 erg cm-1s-1 Products: Light curve | Spectrum
2 [details]	23h 48m 19.49s357.08120°	-75° 52′ 14.4″-75.87068°	6.4′′	Good	3 (U)	4.8′	6.3 ks	Matches SIMBAD source: LEDA 242511, 4.1″ away.
Mean XRT rate: 7.6 (+1.6, -1.4) ×10-3 ct s-1 Peak XRT rate: 8.6 (+2.9, -2.4) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 5.78 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 6.9 (+1.4, -1.3) ×10-5 ct s-1 Peak XRT rate converted to PSPC: 7.8 (+2.6, -2.2) ×10-5 ct s-1 Mean XRT flux: 7.7 (+1.6, -1.5) ×10-13 erg cm-1s-1 Peak XRT flux: 8.8 (+3.0, -2.5) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum
3 [details]	23h 48m 17.67s357.07363°	-75° 51′ 15.8″-75.85438°	8.0′′ *	Good	3 (U)	5.7′	6.3 ks
Mean XRT rate: 4.6 (+2.2, -1.7) ×10-3 ct s-1 Peak XRT rate: 4.6 (+2.2, -1.7) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.07 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 4.4 (+2.0, -1.6) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 4.4 (+2.0, -1.6) ×10-3 ct s-1 Mean XRT flux: 3.2 (+1.5, -1.2) ×10-13 erg cm-1s-1 Peak XRT flux: 3.2 (+1.5, -1.2) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum | Enhanced position
4 [details]	23h 47m 56.63s356.98596°	-75° 50′ 11.8″-75.83662°	6.4′′	Reasonable	3 (U)	6.6′	6.3 ks
Mean XRT rate: 2.0 (+0.9, -0.7) ×10-3 ct s-1 Peak XRT rate: 3.0 (+1.7, -1.3) ×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: 2.87 (+1.28, -0.93) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 4.2 (+2.5, -1.8) ×10-3 ct s-1 Mean XRT flux: 7.1 (+3.1, -2.3) ×10-14 erg cm-1s-1 Peak XRT flux: 1.0 (+0.6, -0.4) ×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.

Image

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FITS image.

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Exposure map

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FITS exposure map.