GCN Circular 21318

K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N.
Burrows (PSU), A. Cholden-Brown (PSU), B. Mingo (U. Leicester), A.P.
Beardmore (U. Leicester), A.A. Breeveld (MSSL/UCL), S.B. Cenko (GSFC)
and P.A. Evans (U. Leicester) report on behalf of the Swift team:

Swift has performed follow-up observations of the BAT and
Fermi/GBM-detected burst GRB 170710B (Palmer & Lien, GCN Circ. 21316
Not found
 
 
),
collecting 4.0 ks of Photon Counting (PC) mode data between T0+85.2 ks
and T0+92.7 ks. 

One uncatalogued X-ray source has been detected consistent with being
within 296 arcsec of the BAT position; it is below the RASS limit and
shows no definitive signs of fading. It is 4.8" from SDSS
J025227.08+423819.4, which is a possible quasar, therefore more data
are needed to confirm whether the XRT source is the GRB afterglow.
Further observations are planned. Details of this source are given
below:

Source 1:
  RA (J2000.0):  43.1110  =  02:52:26.65
  Dec (J2000.0): +42.6391  =  +42:38:20.7
  Error: 3.3 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (6.4 [+1.6, -1.4])e-3 ct s^-1   
  Distance: 146 arcsec from BAT position.
  Flux: (2.51 [+0.61, -0.56])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)


The UVOT started observing this source 85.2 ks after the burst. The
catalogued source just on the edge of the XRT region is detected, but
no new source is found to an upper limit in the UVW2 filter of 21.3 mag
in 3924s of exposure.

Two uncatalogued X-ray 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
http://www.swift.ac.uk/ToO_GRBs/00020777.

This circular is an official product of the Swift2 team.