TITLE:   GCN CIRCULAR
NUMBER:  43388
SUBJECT: GRB 260111A: Swift-XRT observations
DATE:    26/01/13 11:01:35 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

S. Lanava (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester),
A.P. Beardmore (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia
(SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), S. Dichiara (PSU), J.A.
Kennea (PSU) and P.A. Evans (U. Leicester) reports on behalf of the
Swift-XRT team:

Swift-XRT has performed follow-up observations of the Swift/BAT-GUANO
(Ronchini et al., GCN 43377) and Fermi/GBM (Fermi GBM team, GCN 43370;
Palafox et al., GCN 43384) detected burst GRB 260111A, collecting  2.8
ks of Photon Counting (PC) mode data between T0+94.3 ks and T0+104.8
ks. 

One uncatalogued X-ray source has been detected within the estimated
3-sigma Swift/BAT error region (493 arcsec), it is below the RASS limit
and shows no definitive signs of fading. A source consistent with the
position of XRT source 2 has been reported in the optical with
COLIBRÍ,  suggesting it could be the GRB afterglow (Ducoin et al., GCN
43386). 

Details of this source are given below:

Source 2:
  RA (J2000.0):  229.5858  =  15h 18m 20.60s
  Dec (J2000.0): +51.9736  =  +51d 58' 24.8"
  Error: 6.3 arcsec (radius, 90% conf.)
  Count-rate: (5.6 [+2.4, -1.9])e-3 ct s^-1   
  Distance: 27 arcsec from Swift/BAT position.
  Flux: (1.56 [+0.66, -0.53])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

A catalogued source was also detected within the estimated 3-sigma
Swift/BAT error region (493 arcsec).

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/00021897.

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