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GCN Circular 31064

Subject

GRB 211107B: Swift-XRT observations

Date

2021-11-09T16:34:27Z (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), 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. 31057Not found
 
 
), 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
https://www.swift.ac.uk/ToO_GRBs/00021467.

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