EP250109a / GRB 250109A: Swift observation summary

Mission:	Einstein Probe/WXT
Einstein Probe RA:	88.806°
Einstein Probe Dec:	-12.500°
Einstein Probe Err:	3.0 arcmin
T0:	2025-01-09 06:17:58 UT
Galactic:	218.03° -18.04°
Galactic N_H:	1.68× 10²¹ cm^-2

Sun distance:	139.40°
Sun angle:	10.55 [hr](East of Sun)
Moon distance:	54.54°
Visibility of this field.
First slew:	2025-01-09 09:19:46 UT
First observation:	2025-01-09 09:19:10 UT
First analysis:	2025-01-09 11:51:59 UT

Data analysed so far:

ObsID: 00019015001 with 1.0 ks exposure.
ObsID: 00019015002 with 3.1 ks exposure.

About tiled field analysis.

So far 1 fields have been scheduled for observations. Data are available and processed for 1 of these.

1 fields were processed but not included in the analysis. This is because, after standard processing and the removal of times contaminated by light reflected off the bright Earth, there was too little data (<100 s) for source detection to be performed.

Find an upper limit.

Sources found so far

So far 6 sources have been found in the XRT data. 1 sources match catalogued sources.

#	RA (J2000)	Dec (J2000)	Err₉₀¹	Detection Flag²	Rank³	Dist from Einstein Probe/WXT pos	Exposure	Notes
1 [details]	05h 55m 07.86s88.78275°	-12° 21′ 58.6″-12.36628°	6.8′′	Good	3 (U)	8.1′	4.1 ks
Mean XRT rate: 1.5 (+1.0, -0.7) ×10^-3 ct s^-1 Peak XRT rate: 1.5 (+1.0, -0.7) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.02 ct s^-1 (PSPC count-rate) Products: Light curve \| Spectrum
2 [details]	05h 55m 36.12s88.90051°	-12° 21′ 19.8″-12.35549°	6.9′′	Good	3 (U)	10.3′	4.1 ks
Mean XRT rate: 3.5 (+1.4, -1.1) ×10^-3 ct s^-1 Peak XRT rate: 3.5 (+1.4, -1.1) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 43484081429990.10 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 3.5 (+1.4, -1.1) ×10^-18 ct s^-1 Peak XRT rate converted to PSPC: 3.5 (+1.4, -1.1) ×10^-18 ct s^-1 Mean XRT flux: 2.3 (+1.0, -0.8) ×10^-10 erg cm^-1s^-1 Peak XRT flux: 2.3 (+1.0, -0.8) ×10^-10 erg cm^-1s^-1 Products: Light curve \| Spectrum
3 [details]	05h 55m 13.67s88.80698°	-12° 29′ 44.8″-12.49579°	5.8′′	Good	3 (U)	0.3′	4.1 ks
Mean XRT rate: 2.03 (+1.07, -0.81) ×10^-3 ct s^-1 Peak XRT rate: 2.03 (+1.07, -0.81) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.02 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 2.6 (+1.4, -1.1) ×10^-3 ct s^-1 Peak XRT rate converted to PSPC: 2.6 (+1.4, -1.1) ×10^-3 ct s^-1 Mean XRT flux: 4.7 (+2.5, -1.9) ×10^-14 erg cm^-1s^-1 Peak XRT flux: 4.7 (+2.5, -1.9) ×10^-14 erg cm^-1s^-1 Products: Light curve \| Spectrum
4 [details]	05h 55m 22.67s88.84446°	-12° 21′ 45.0″-12.36250°	7.1′′	Good	3 (U)	8.6′	4.1 ks	Matches SIMBAD source: TYC 5356-516-1, 10.1″ away.
Mean XRT rate: 2.35 (+1.19, -0.90) ×10^-3 ct s^-1 Peak XRT rate: 2.35 (+1.19, -0.90) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.01 ct s^-1 (PSPC count-rate) Mean XRT rate converted to PSPC: 5.3 (+2.7, -2.0) ×10^-3 ct s^-1 Peak XRT rate converted to PSPC: 5.3 (+2.7, -2.0) ×10^-3 ct s^-1 Mean XRT flux: 3.3 (+1.7, -1.3) ×10^-14 erg cm^-1s^-1 Peak XRT flux: 3.3 (+1.7, -1.3) ×10^-14 erg cm^-1s^-1 Products: Light curve \| Spectrum
5 [details]	05h 55m 00.75s88.75311°	-12° 27′ 46.3″-12.46287°	6.3′′	Reasonable	3 (U)	3.8′	4.1 ks
Mean XRT rate: 1.6 (+1.0, -0.7) ×10^-3 ct s^-1 Peak XRT rate: 1.6 (+1.0, -0.7) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.01 ct s^-1 (PSPC count-rate) Products: Light curve \| Spectrum
6 [details]	05h 54m 53.26s88.72193°	-12° 34′ 33.8″-12.57605°	6.4′′	Poor	3 (U)	6.7′	4.1 ks
Mean XRT rate: 1.3 (+0.9, -0.7) ×10^-3 ct s^-1 Peak XRT rate: 1.3 (+0.9, -0.7) ×10^-3 ct s^-1 RASS PSPC 3-σ upper limit: 0.02 ct s^-1 (PSPC count-rate) 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.

Exposure map

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FITS exposure map.