GCN Circular 16472

N. P. M. Kuin (UCL-MSSL) and E. Sonbas (NASA/GSFC/Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140628A
278 s after the BAT trigger (Sonbas et al., GCN Circ. 16467
Not found
 
 
).  A source
consistent with the XRT position (D'Avanzo et al. GCN Circ. 16470
Not found
 
 
)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  02:42:39.88 =  40.66617 (deg.)
    Dec (J2000) = -00:23:05.7  =  -0.38491 (deg.)
with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).

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              278          327           48         17.43 +/- 0.08
white             3593         4974          300        >21.0
v                 3749         3949          197         19.08 +/- 0.28
b                 4569         4769          197        >20.2
u                 4364         4564          197        >19.5
w1                4159         4359          197        >19.8
m2                3954         4154          197        >21.2
w2                9366        10266          886        >21.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).