GCN Circular 14937

K.L. Page (U. Leicester), S.R. Oates (UCL-MSSL) and M. De Pasquale
(UCL-MSSL) report on behalf of the Swift-XRT and UVOT teams:

We have analysed 9.5 ks of Swift-XRT Photon Counting mode data collected
for GRB 130626A, starting 111 s after the trigger (De Pasquale et al., GCN
Circ. 14931
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 ). Of these data, only 10s were collected promptly following
the trigger before Swift had to slew away because of a pointing
constraint.

Within the onboard BAT error circle, there is a possible source detected,
with a count rate (averaged between 111 s and 34.7 ks after the trigger)
of (2.0 +0.5/-0.4) x 10^-3 count s^-1. The position of this source is RA,
Dec = 273.14043, -9.50093, which is equivalent to:

RA (J2000):   18h 12m 33.70s
Dec (J2000): -09d 30' 03.3"

with an uncertainty of 5.5 arcsec (radius, 90% confidence). It is not
possible to determine whether this candidate source is fading at present;
a follow-up observation will be performed at a later date.

We do note, however, that there are other possible sources detected at a
similar level in the XRT field of view, although outside the BAT error
circle.

The Swift-UVOT began settled observations of the field of GRB 130626A
67 s after the BAT trigger (De Pasquale et al., GCN Circ. 14931
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 ).
In the initial UVOT exposures, no optical afterglow is found within
the BAT error circle or consistent with the candidate XRT position.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial
exposures are:

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

white (FC)          67          124          57          >20.5
white               67         5608          597         >22.0
v                 4384         5892          269         >19.8
b                 3768         5403          393         >21.1
u                 3563         5198          393         >20.7
w1                4794         4993          197         >20.1

The magnitudes in the table are not corrected for the heavy, but
uncertain, Galactic extinction due to the reddening of E(B-V) = 1.45 in
the direction of the burst (Schlegel et al. 1998).

This circular is an official product of the Swift-XRT and UVOT teams.