GRB 250916A: Swift observation summary

Mission:	Fermi/GBM
GRB RA:	26.570°
GRB Dec:	+36.165°
GRB Err:	0.498 arcsec
T0:	2025-09-16 13:29:21 UT
Galactic:	135.16° -25.40°
Galactic N_H:	4.57× 10²⁰ cm^-2
Galactic E(B-V):	0.05220231

Sun distance:	130.86°
Sun angle:	9.83 [hr](West of Sun)
Moon distance:	72.35°
Visibility of this field.

Data analysed so far:

ObsID: 00021859001 with 1.6 ks exposure.

Source 1 has been manually confirmed as the GRB afterglow; data for this object are now available through the main GRB results area for this GRB.

About ToO analysis.

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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	Dist from Fermi/GBM pos	Exposure
1 [details]	01h 46m 16.99s26.57080°	+36° 09′ 54.6″36.16517°	3.7′′	Good	2.4′′	1.6 ks
Mean XRT rate: 2.7 (±0.5) ×10^-2 ct s^-1 Peak XRT rate: 3.0 (±0.8) ×10^-2 ct s^-1 RASS PSPC 3-σ upper limit: 0.03 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 9.2 (±1.6) ×10^-13 erg cm^-1s^-1 Peak XRT flux: 1.00 (±0.27) ×10^-12 erg cm^-1s^-1 Products: Light curve \| Spectrum \| Enhanced position \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?]
2 [details]	01h 45m 15.27s26.31363°	+36° 08′ 39.5″36.14432°	8.7′′	Poor	12.5′	930 s
Mean XRT rate: 1.3 (+0.6, -0.5) ×10^-2 ct s^-1 Peak XRT rate: 1.3 (+0.6, -0.5) ×10^-2 ct s^-1 RASS PSPC 3-σ upper limit: 15654322.62 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 8 (+4, -3) ×10^-9 erg cm^-1s^-1 Peak XRT flux: 8 (+4, -3) ×10^-9 erg cm^-1s^-1 Products: Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?]

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.