TITLE:   GCN CIRCULAR
NUMBER:  40027
SUBJECT: GRB 250402A: Swift-XRT observations
DATE:    25/04/03 16:01:19 GMT
FROM:    Simone Dichiara at Pennsylvania State University <sbd5667@psu.edu>

S. Dichiara (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB), K.L. 
Page and P.A. Evans (U.Leicester) reports on behalf of the Swift-XRT team:

We have analysed 2.4 ks of XRT data for the SVOM/ECLAIRs-detected burst
GRB 250402A (SVOM trigger sb25040203; Chen et al., GCN circ. 40014), from 
T0+49.2 ks to T0+51.5 ks after the  SVOM/ECLAIRs trigger. The data are 
entirely in Photon Counting (PC) mode.

We find an uncatalogued X-ray source consistent with the X-ray counterpart 
identified by SVOM/MXT (Maggi et al., GCN circ. 40019) and the optical 
counterpart (Xin et al., GCN 40015, Pérez-Fournon et al., GCN 40020, 
Schneider et al., GCN 40022, Magnani et al., GCN 40023). We note that the 
source is fading compared to the flux reported by previous MXT observations 
(Maggi et al., GCN circ. 40019). 
Details of this source are given below:

Source 1:
  RA (J2000.0):  213.4089  =  14:13:38.13
  Dec (J2000.0): -5.9302  =  -05:55:48.5
  Error: 3.4 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate:0.045 (±0.012) ct s-1   
  Flux: 1.9 (±0.5) ×10-12 erg cm-2 s-1 (observed, 0.3-10 keV)

This XRT position is 1.07 arcsec away from the optical position.
The results of the XRT-team automatic analysis of the XRT observations, 
including a position-specific upper limit calculator, are available at 
https://www.swift.ac.uk/SVOM/SVOM_FIELD00009/.

This circular is an official product of the Swift-XRT team.