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GCN Circular 31866

Subject
GRB 220403C: Swift-XRT observations
Date
2022-04-09T18:56:40Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), A. D'Ai
(INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea
(PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P.
Beardmore (U. Leicester) and P.A. Evans (U. Leicester) report on behalf
of the Swift-XRT team:

Swift-XRT has performed follow-up observations of GRB 220403C, detected
outside the BAT coded FOV by GUANO NITRATES (Aaron Tohuvavohu et al.
GCN Circ. 31824Loading...
 
 ), as well as by Fermi-GBM, INTEGRAL, CALET and
ISS-ASIM, collecting 3.2 ks of Photon Counting (PC) mode data between
T0+497.7 ks and T0+528.5 ks. 

Six uncatalogued X-ray sources have been detected, however none of them
is above the RASS limit or shows definitive signs of fading. Therefore,
at the present time we cannot identify which, if any, is the afterglow.
Details of these sources are given below:

Source 1:
  RA (J2000.0):  19.7120  =  01:18:50.87
  Dec (J2000.0): -56.4530  =  -56:27:10.8
  Error: 11.4 arcsec (radius, 90% conf.)
  Count-rate: (3.7 [+3.1, -2.2])e-3 ct s^-1   
  Distance: 515 arcsec from ASIM position.

Source 2:
  RA (J2000.0):  19.6293  =  01:18:31.04
  Dec (J2000.0): -56.3726  =  -56:22:21.5
  Error: 8.4 arcsec (radius, 90% conf.)
  Count-rate: (3.8 [+3.0, -2.2])e-3 ct s^-1   
  Distance: 530 arcsec from ASIM position.

Source 3:
  RA (J2000.0):  19.7466  =  01:18:59.17
  Dec (J2000.0): -56.4578  =  -56:27:28.0
  Error: 9.1 arcsec (radius, 90% conf.)
  Count-rate: (6.2 [+3.7, -2.8])e-3 ct s^-1   
  Distance: 484 arcsec from ASIM position.

Source 4:
  RA (J2000.0):  19.7142  =  01:18:51.41
  Dec (J2000.0): -56.2603  =  -56:15:37.1
  Error: 6.7 arcsec (radius, 90% conf.)
  Count-rate: (4.3 [+1.7, -1.3])e-3 ct s^-1   
  Distance: 479 arcsec from ASIM position.
  Flux: (2.90 [+1.13, -0.91])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)


Source 5:
  RA (J2000.0):  19.7189  =  01:18:52.53
  Dec (J2000.0): -56.2878  =  -56:17:16.2
  Error: 6.8 arcsec (radius, 90% conf.)
  Count-rate: (1.17 [+1.01, -0.72])e-3 ct s^-1	 
  Distance: 411 arcsec from ASIM position.

Source 6:
  RA (J2000.0):  19.9526  =  01:19:48.63
  Dec (J2000.0): -56.2605  =  -56:15:37.7
  Error: 6.8 arcsec (radius, 90% conf.)
  Count-rate: (2.13 [+1.25, -0.92])e-3 ct s^-1	 
  Distance: 344 arcsec from ASIM 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/ToO_GRBs/00021484.

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