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Home > SVOM follow up > GRB 250727A

SVOM_FIELD00025

SVOM

25

/SVOM

GRB 250727A: Swift observation summary

This is a confirmed GRB (GRB 250727A), the afterglow is source 1 -- please see the GRB results at https://www.swift.ac.uk/xrt_products/00019965 for updated analysis

Data analysed so far:

• ObsID: 00019965001 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.

• 19965 — 1.6 ks of cleaned data taken between 2025-07-27 11:31:01 and 2025-07-27 13:11:17

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 45m 39.52s356.41465°	-81° 12′ 50.4″-81.21400°	4.2′′ *	Good	2 (O)	7.7′	5.9 ks	The source is fading with 3.7-σ significance.
Mean XRT rate: 1.3 (±0.3) ×10-2 ct s-1 Peak XRT rate: 1.3 (±0.3) ×10-2 ct s-1 RASS PSPC 3-σ upper limit: 0.05 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.017 (±0.004) ct s-1 Peak XRT rate converted to PSPC: 0.017 (±0.004) ×10-2 ct s-1 Mean XRT flux: 4.1 (±1.1) ×10-13 erg cm-1s-1 Peak XRT flux: 4.1 (±1.1) ×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 2 sources have been found in the XRT data. 0 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err901	Detection Flag2	Rank3	Dist from SVOM/ECLAIRs pos	Exposure	Notes	Vizier
1 [details]	23h 45m 39.52s356.41465°	-81° 12′ 50.4″-81.21400°	4.2′′ *	Good	2 (O)	7.7′	5.9 ks	The source is fading with 3.7-σ significance.
Mean XRT rate: 1.3 (±0.3) ×10-2 ct s-1 Peak XRT rate: 1.3 (±0.3) ×10-2 ct s-1 RASS PSPC 3-σ upper limit: 0.05 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 0.017 (±0.004) ct s-1 Peak XRT rate converted to PSPC: 0.017 (±0.004) ×10-2 ct s-1 Mean XRT flux: 4.1 (±1.1) ×10-13 erg cm-1s-1 Peak XRT flux: 4.1 (±1.1) ×10-13 erg cm-1s-1 Products: Light curve | Spectrum | Enhanced position
2 [details]	23h 44m 06.83s356.02844°	-81° 03′ 15.6″-81.05434°	8.5′′	Good	3 (U)	4.9′	5.9 ks
Mean XRT rate: 2.6 (+1.0, -0.7) ×10-3 ct s-1 Peak XRT rate: 5.2 (+2.6, -2.0) ×10-3 ct s-1 RASS PSPC 3-σ upper limit: 0.05 ct s-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 2.4 (+0.9, -0.7) ×10-3 ct s-1 Peak XRT rate converted to PSPC: 4.9 (+2.5, -1.9) ×10-3 ct s-1 Mean XRT flux: 1.3 (+0.5, -0.4) ×10-13 erg cm-1s-1 Peak XRT flux: 2.7 (+1.4, -1.0) ×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.