GCN Circular 18018

A. Melandri (INAF-OAB), P. Kuin (MSSL-UCL), V. D'Elia (ASDC), A. D'ai
(INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester),
A.P. Beardmore (U. Leicester), A. Maselli (INAF-IASFPA) 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 150710B (Cummings et al. GCN Circ. 18009
Not found
 
 
),
collecting 2.8 ks of Photon Counting (PC) mode data between T0+115.2 ks
and T0+121.6 ks. 

An uncatalogued X-ray source has been detected close to the refined
Swift/BAT error region (Cummings et al. GCN Circ. 18013
Not found
 
 
), 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:

  RA (J2000.0):  83.2176  =  05:32:52.23
  Dec (J2000.0): -46.9423  =  -46:56:32.4
  Error: 4.7 arcsec (radius, 90% conf.)
  Count-rate: 0.0141 [+0.0031, -0.0027] ct s^-1

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/00020542.

Simultaneous with the Swift-XRT, the Swift-UVOT observed the field
of GRB 150710B. Preliminary 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
for the first finding chart (FC) exposure and subsequent exposures are:


Filter	       T_start(s)   T_stop(s)	   Exp(s)	Mag

white	       115375	    120586	   662	       >21.1
v	       115594	    121561	   957	       >19.5
u	       115157	    120072	   915	       >20.5

The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.04 in the direction of
the burst (Schlegel et al. 1998).

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