GCN Circular 14573

M. De Pasquale (MSSL/UCL) and J. K. Cannizzo (NASA/UMBC) report on behalf
of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130505A
107 s after the BAT trigger (Cannizzo et al., GCN Circ. 14563
Not found
 
 
). A bright 
but
rapidly fading source is detected in the finding chart and initial exposures
within the XRT error circle (Evans et al., GCN Circ. 14569
Not found
 
 
).

The preliminary UVOT position is:
   RA(J2000)  =    09:08:14.64 = 137.0610
   DEC(J2000) =   +17:29:05.2  = +17.48478
with a 90%-confidence error radius of about 0.5 arc sec.

Preliminary detections and 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for
the early exposures are:

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

white (FC)         107          256        147          14.14 � 0.05
white             3952         4151        197          17.96 � 0.07
v                 4362         4561        197          17.50 � 0.11
b                 3503         3946        197          17.71 � 0.08
u                  320          542        218          14.66 � 0.04
uvw1              4772         4971        197          19.28 � 0.29 (~3 
sigma)
uvm2              4567         4766        197          >19.6
uvw2              4158         4357        197          >19.9

The non-detection of the optical source in um2 and uw2 filters is
consistent with the redshift z=2.27 found by Tanvir et al (GCN Circ. 14567
Not found
 
 
)

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).