GRB 250330A: Swift observation summary

Mission:	Swift-BAT
GRB RA:	252.790°
GRB Dec:	-86.870°
GRB Err:	3.0 arcmin
T0:	2025-03-30 06:07:38 UT
Galactic:	305.93° -25.53°
Galactic N_H:	8.32× 10²⁰ cm^-2
Galactic E(B-V):	0.1349984

Sun distance:	95.10°
Sun angle:	7.56 [hr] (West of Sun)
Moon distance:	101.87°
Visibility of this field.

Data analysed so far:

ObsID: 01299776000 with 1.2 ks exposure.
ObsID: 01299776001 with 0.2 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.

Probable afterglow details

A source was found which matches the afterglow criteria.

#	RA (J2000)	Dec (J2000)	Err₉₀¹	Detection Flag²	Dist from Swift-BAT pos	Exposure	Notes	Vizier
1 [details]	16h 51m 44.91s252.93712°	-86° 52′ 47.8″-86.87996°	3.7′′	Good	0.8′	1.4 ks	The source is fading with 3.3-σ significance. The source is 4.5-σ above the LSXPS limit.
Mean XRT rate: 0.163 (±0.012) ct s^-1 Peak XRT rate: 0.26 (±0.06) ct s^-1 RASS PSPC 3-σ upper limit: 0.08 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 5.4 (±0.4) ×10^-12 erg cm^-1s^-1 Peak XRT flux: 8.6 (±1.9) ×10^-12 erg cm^-1s^-1 Products: Light curve \| 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 2SXPS 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.

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	Dist from Swift-BAT pos	Exposure	Notes
1 [details]	16h 51m 44.91s252.93712°	-86° 52′ 47.8″-86.87996°	3.7′′	Good	0.8′	1.4 ks	The source is fading with 3.3-σ significance. The source is 4.5-σ above the LSXPS limit.
Mean XRT rate: 0.163 (±0.012) ct s^-1 Peak XRT rate: 0.26 (±0.06) ct s^-1 RASS PSPC 3-σ upper limit: 0.08 ct s^-1 (XRT equiv count-rate) Mean XRT flux: 5.4 (±0.4) ×10^-12 erg cm^-1s^-1 Peak XRT flux: 8.6 (±1.9) ×10^-12 erg cm^-1s^-1 Products: Light curve \| Spectrum \| Expected serendipitous sources: ~0.00×10⁺⁰ [What is this?]
2 [details]	16h 54m 02.42s253.51009°	-86° 48′ 02.6″-86.80072°	6.3′′	Reasonable	4.8′	1.4 ks
Mean XRT rate: undetermined ct s^-1 Peak XRT rate: undetermined ct s^-1 RASS PSPC 3-σ upper limit: 0.03 ct s^-1 (XRT equiv count-rate) 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.