GCN Circular 33029

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo
(INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi  (INAF-IASFPA) ,
D.N. Burrows (PSU), J. D. Gropp (PSU), S. Dichiara (PSU), 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 the
Swift/BAT-GUANO-detected burst GRB 221206B, collecting 4.8 ks of Photon
Counting (PC) mode data between T0+28.7 ks and T0+45.0 ks. 

No X-ray sources have been detected within the Swift/BAT-GUANO error
circle. The 3-sigma upper limit in the field ranges from ~0.002 to
~0.003 ct s^-1, corresponding to a 0.3-10 keV observed flux of 7.7e-14
to 1.0e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

Five uncatalogued sources were 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/00021532.

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