GRB 250804B: Swift observation summary

Mission:	IPN
GRB RA:	40.607°
GRB Dec:	-46.768°
GRB Err:	17.0 arcmin
T0:	2025-08-04 04:44:51 UT
Galactic:	262.33° -60.66°
Galactic N_H:	1.81× 10²⁰ cm^-2
Galactic E(B-V):	0.01864426

Sun distance:	104.90°
Sun angle:	6.25 [hr](West of Sun)
Moon distance:	101.82°
Visibility of this field.
First slew:	2025-08-05 04:45:10 UT
First observation:	2025-08-05 02:49:56 UT
First analysis:	UT

About tiled field analysis.

So far 3 fields have been scheduled for observations. Data are available and processed for 3 of these. The list gives the exposure time used in source detection. If any individual sources were selected for follow-up observations, the source detection is not repeated for the follow up observations and the table below is not updated.

21853 — 1.0 ks of cleaned data taken between 2025-08-05 02:50:25 and 2025-08-05 03:08:23
21854 — 942 s of cleaned data taken between 2025-08-05 03:08:26 and 2025-08-05 04:40:49
21855 — 1.3 ks of cleaned data taken between 2025-08-05 04:40:52 and 2025-08-05 06:21:46

Find an upper limit.

Sources found so far

So far 8 sources have been found in the XRT data. 4 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err₉₀¹	Detection Flag²	Dist from IPN pos	Exposure	Notes
1 [details]	02h 42m 08.25s40.53438°	-46° 31′ 37.7″-46.52713°	7.3′′	Good	14.8′	942 s	This source may be affected by optical loading Matches known X-ray source: XMMSL3 J024208.6-463130 (from XMM-NEWTON/XMMSLEWCLN), 8.2″ away. Matches SIMBAD source: HD 17006, 9.9″ away.
Mean XRT rate: 6.2 (±1.0) ×10^-2 ct s^-1 Peak XRT rate: 6.2 (±1.4) ×10^-2 ct s^-1 RASS PSPC 3-σ upper limit: 0.0×10⁰ ct s^-1 (XRT equiv count-rate) Mean XRT flux: 1.20 (±0.20) ×10^-12 erg cm^-1s^-1 Peak XRT flux: 1.19 (±0.26) ×10^-12 erg cm^-1s^-1 Products: Light curve \| Spectrum
2 [details]	02h 42m 43.22s40.68010°	-46° 51′ 38.0″-46.86056°	6.5′′	Good	6.3′	1.0 ks	Matches known X-ray source: 1RXS J024241.0-465149 (from ROSAT/RASSFSC), 25.3″ away.
Mean XRT rate: 6.3 (+3.6, -2.6) ×10^-3 ct s^-1 Peak XRT rate: 6.3 (+3.6, -2.6) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.0×10⁰ ct s^-1 (XRT equiv count-rate) Products: Spectrum
3 [details]	02h 40m 46.19s40.19246°	-46° 34′ 40.8″-46.57799°	6.7′′	Good	20.5′	942 s	Matches known X-ray source: XMMSL3 J024045.9-463439 (from XMM-NEWTON/XMMSLEWCLN), 5.6″ away. Matches SIMBAD source: WISE J024046.97-463431.5, 9.7″ away.
Mean XRT rate: 1.8 (+0.6, -0.5) ×10^-2 ct s^-1 Peak XRT rate: 1.8 (+0.6, -0.5) ×10^-2 ct s^-1 RASS PSPC 3-σ upper limit: 0.0×10⁰ ct s^-1 (XRT equiv count-rate) Mean XRT flux: 1.2 (+0.4, -0.3) ×10^-12 erg cm^-1s^-1 Peak XRT flux: 1.2 (+0.4, -0.3) ×10^-12 erg cm^-1s^-1 Products: Spectrum \| Enhanced position
4 [details]	02h 42m 31.85s40.63272°	-46° 33′ 01.9″-46.55052°	6.4′′	Good	13.1′	1.7 ks	Matches known X-ray source: 1RXS J024232.6-463234 (from ROSAT/RASSFSC), 28.9″ away.
Mean XRT rate: 1.3 (±0.4) ×10^-2 ct s^-1 Peak XRT rate: 1.3 (±0.4) ×10^-2 ct s^-1 RASS PSPC 3-σ upper limit: 0.0×10⁰ ct s^-1 (XRT equiv count-rate) Mean XRT flux: 3.38 (+1.09, -0.91) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 3.38 (+1.09, -0.91) ×10^-13 erg cm^-1s^-1 Products: Spectrum
5 [details]	02h 43m 55.09s40.97953°	-46° 35′ 30.2″-46.59171°	6.8′′	Good	18.6′	1.3 ks
Mean XRT rate: 6.1 (+3.1, -2.3) ×10^-3 ct s^-1 Peak XRT rate: 6.1 (+3.1, -2.3) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.01 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 1.6 (+0.8, -0.6) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 1.6 (+0.8, -0.6) ×10^-13 erg cm^-1s^-1 Products: Spectrum
6 [details]	02h 43m 28.64s40.86935°	-46° 28′ 54.4″-46.48178°	7.1′′	Poor	20.3′	1.3 ks
Mean XRT rate: 10 (+4, -3) ×10^-3 ct s^-1 Peak XRT rate: 10 (+4, -3) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.03 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 1.8 (+0.7, -0.6) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 1.8 (+0.7, -0.6) ×10^-13 erg cm^-1s^-1 Products: Spectrum
7 [details]	02h 42m 11.74s40.54891°	-46° 30′ 51.5″-46.51431°	8.8′′	Poor	15.4′	942 s
Mean XRT rate: 9 (+5, -4) ×10^-3 ct s^-1 Peak XRT rate: 9 (+5, -4) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.12 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 3.0 (+1.6, -1.2) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 3.0 (+1.6, -1.2) ×10^-13 erg cm^-1s^-1 Products: Spectrum
8 [details]	02h 42m 41.22s40.67175°	-46° 44′ 00.9″-46.73359°	6.7′′	Reasonable	3.4′	2.3 ks
Mean XRT rate: 4.2 (+2.3, -1.7) ×10^-3 ct s^-1 Peak XRT rate: 4.2 (+2.3, -1.7) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.02 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 1.0 (+0.5, -0.4) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 1.0 (+0.5, -0.4) ×10^-13 erg cm^-1s^-1 Products: Spectrum

¹ Radius, 90% confidence.
² Indicates how likely the source is to be real. See the 1SXPS documentation.
^* 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.

Exposure map

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FITS exposure map.