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GCN Circular 31064

GRB 211107B: Swift-XRT observations
2021-11-09T16:34:27Z (2 years ago)
Phil Evans at U of Leicester <>
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.
Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Swift/BAT-detected burst GRB 211107B (Swift/BAT did not successfully
trigger on GRB 211107B et al. GCN Circ. 31057), collecting 1.7 ks of
Photon Counting (PC) mode data between T0+124.3 ks and T0+131.0 ks. 

One uncatalogued X-ray source has been detected consistent with being
within 197 arcsec of the Swift/BAT position, it is below the RASS limit
and shows no definitive signs of fading. Therefore, at the present time
we cannot confirm this as the afterglow. Details of this source are
given below:

Source 1:
  RA (J2000.0):  65.80807  =  04:23:13.94
  Dec (J2000.0): -27.56097  =  -27:33:39.5
  Error: 2.9 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0220 +/- 0.0042 ct s^-1   
  Distance: 52 arcsec from Swift/BAT position.
  Flux: (5.15 +/- 0.98)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at

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