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GCN Circular 32434

Subject
GRB 220730A: Swift-XRT observations
Date
2022-07-31T16:16:31Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A.
Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester),
A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) and S. Dichiara (PSU)
report on behalf of the Swift-XRT team:

We have analysed 5.7 ks of Photon Counting (PC) mode XRT data for the
Swift-BAT-detected burst GRB 220730A (Dichiara et al. GCN Circ. 32431),
collected between T0+3.8 ks and T0+51.6 ks. 

Four uncatalogued X-ray sources have been detected consistent with
being within 296 arcsec of the Swift-BAT position, 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):  224.9153  =  14:59:39.66
  Dec (J2000.0): -69.5540  =  -69:33:14.4
  Error: 6.4 arcsec (radius, 90% conf.)
  Count-rate: (1.27 [+0.69, -0.53])e-3 ct s^-1	 
  Distance: 244 arcsec from Swift-BAT position.
  Flux: (4.0 [+2.2, -1.7])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 5:
  RA (J2000.0):  225.0143  =  15:00:3.43
  Dec (J2000.0): -69.4959  =  -69:29:45.4
  Error: 6.6 arcsec (radius, 90% conf.)
  Count-rate: (1.90 [+1.02, -0.77])e-3 ct s^-1	 
  Distance: 9 arcsec from Swift-BAT position.
  Flux: (4.0 [+2.2, -1.6])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 7:
  RA (J2000.0):  225.0749  =  15:00:17.98
  Dec (J2000.0): -69.4908  =  -69:29:26.9
  Error: 7.3 arcsec (radius, 90% conf.)
  Count-rate: (1.68 [+0.79, -0.62])e-3 ct s^-1	 
  Distance: 71 arcsec from Swift-BAT position.
  Flux: (1.12 [+0.53, -0.41])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 8:
  RA (J2000.0):  224.9654  =  14:59:51.71
  Dec (J2000.0): -69.5389  =  -69:32:20.2
  Error: 7.4 arcsec (radius, 90% conf.)
  Count-rate: (2.53 [+0.93, -0.76])e-3 ct s^-1	 
  Distance: 166 arcsec from Swift-BAT position.
  Flux: (3.13 [+1.15, -0.94])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Five uncatalogued sources were also detected too far from the GRB
position to be likely afterglow candidates.

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/01118357.

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