GCN Circular 16273

S. R. Oates (IAA-CSIC,UCL-MSSL) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140515A
79 s after the BAT trigger (D'Avanzo et al., GCN Circ. 16267
Not found
 
 
).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 16270
Not found
 
 
) is detected in the initial UVOT exposures.
The lack of detection in all UVOT filters is consistent with a redshift of  
6.32 (Chornock et al., GCN Circ. 16269
Not found
 
 
).

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_FC            79          229          147         >20.7
u_FC               293          542          246         >20.0
white               79         7407          638         >21.5
v                  628         7818          471         >19.7
b                  548         7202          456         >20.6
u                  293        13671          1398        >20.9
w1                1618        12925          1140        >20.9
m2                6387        12019          1082        >20.6
w2                5977         7612          393         >20.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).