GRB 250917B: Swift observation summary

Mission:	Swift-BAT
GRB RA:	291.378°
GRB Dec:	+11.113°
GRB Err:	3.0 arcmin
T0:	2025-09-17 06:27:44 UT
Galactic:	46.70° -2.38°
Galactic N_H:	5.82× 10²¹ cm^-2
Galactic E(B-V):	1.897327

Sun distance:	115.59°
Sun angle:	7.77 [hr] (East of Sun)
Moon distance:	143.06°
Visibility of this field.

Data analysed so far:

ObsID: 01350381000 with 1.7 ks exposure.
ObsID: 01350381001 with 3.8 ks exposure.
ObsID: 01350381002 with 4.0 ks exposure.

About ToO analysis.

Find an upper limit.

Sources found so far

So far 9 sources have been found in the XRT data. 3 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err₉₀¹	Detection Flag²	Dist from Swift-BAT pos	Exposure	Notes
1 [details]	19h 25m 23.00s291.34584°	+11° 06′ 54.5″11.11514°	5.5′′	Good	1.9′	9.5 ks	Matches SIMBAD source: TYC 1059-317-1, 2.1″ away.
Mean XRT rate: 5.7 (±1.0) ×10^-3 ct s^-1 Peak XRT rate: 5.7 (±1.3) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.02 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 1.45 (±0.24) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 1.4 (±0.3) ×10^-13 erg cm^-1s^-1 Products: Light curve \| Spectrum \| Enhanced position \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°
2 [details]	19h 26m 04.84s291.52017°	+11° 10′ 16.1″11.17115°	6.4′′	Poor	9.1′	9.5 ks
Mean XRT rate: undetermined ct s^-1 Peak XRT rate: undetermined ct s^-1 RASS PSPC 3-σ upper limit: 0.01 ct s^-1 (XRT equiv count-rate) Products: Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°
3 [details]	19h 25m 06.04s291.27516°	+11° 00′ 27.1″11.00752°	6.6′′	Poor	8.8′	9.5 ks	Matches SIMBAD source: 2MASS J19250566+1100103, 17.4″ away.
Mean XRT rate: 3.4 (+0.9, -0.7) ×10^-3 ct s^-1 Peak XRT rate: 4.0 (+1.5, -1.2) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.06 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 2.3 (+0.6, -0.5) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 2.71 (+1.03, -0.84) ×10^-13 erg cm^-1s^-1 Products: Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°
4 [details]	19h 25m 04.61s291.26919°	+11° 05′ 24.1″11.09003°	6.3′′	Reasonable	6.6′	9.5 ks
Mean XRT rate: undetermined ct s^-1 Peak XRT rate: undetermined ct s^-1 RASS PSPC 3-σ upper limit: 0.15 ct s^-1 (XRT equiv count-rate) Mean XRT flux: undetermined erg cm^-1s^-1 Peak XRT flux: undetermined erg cm^-1s^-1 Products: Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°
5 [details]	19h 25m 34.30s291.39290°	+11° 04′ 29.2″11.07477°	7.7′′	Poor	2.5′	9.5 ks
Mean XRT rate: undetermined ct s^-1 Peak XRT rate: undetermined ct s^-1 RASS PSPC 3-σ upper limit: 0.01 ct s^-1 (XRT equiv count-rate) Products: Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°
6 [details]	19h 25m 43.49s291.43120°	+11° 06′ 05.0″11.10139°	8.3′′	Poor	3.2′	9.5 ks	Matches SIMBAD source: ZTF J192541.95+110559.7, 23.1″ away.
Mean XRT rate: undetermined ct s^-1 Peak XRT rate: undetermined ct s^-1 RASS PSPC 3-σ upper limit: 0.0×10⁰ ct s^-1 (XRT equiv count-rate) Mean XRT flux: undetermined erg cm^-1s^-1 Peak XRT flux: undetermined erg cm^-1s^-1 Products: Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°
7 [details]	19h 25m 01.80s291.25750°	+11° 03′ 01.8″11.05051°	7.7′′	Poor	8.0′	9.5 ks
Mean XRT rate: undetermined ct s^-1 Peak XRT rate: undetermined ct s^-1 RASS PSPC 3-σ upper limit: 0.01 ct s^-1 (XRT equiv count-rate) Products: Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°
8 [details]	19h 25m 23.48s291.34782°	+11° 01′ 49.7″11.03047°	6.2′′	Poor	5.3′	9.5 ks
Mean XRT rate: 3.1 (+1.3, -1.1) ×10^-3 ct s^-1 Peak XRT rate: 3.1 (+1.3, -1.1) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 2.81 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 5.0 (+2.1, -1.7) ×10^-94 erg cm^-1s^-1 Peak XRT flux: 5.0 (+2.1, -1.7) ×10^-94 erg cm^-1s^-1 Products: Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°
9 [details]	19h 25m 10.51s291.29379°	+11° 00′ 00.6″11.00017°	6.3′′	Poor	8.4′	9.5 ks
Mean XRT rate: 1.3 (+0.8, -0.6) ×10^-3 ct s^-1 Peak XRT rate: 1.3 (+0.8, -0.6) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.0×10⁰ ct s^-1 (XRT equiv count-rate) Mean XRT flux: 2.06 (+1.23, -0.93) ×10^-12 erg cm^-1s^-1 Peak XRT flux: 2.06 (+1.23, -0.93) ×10^-12 erg cm^-1s^-1 Products: Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?] Note: this is extragalactic sources only, whereas the GRB trigger is at b=-2.38°

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.

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Exposure map

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FITS exposure map.