GCN Circular 19496

S. Sebzda (Penn State/Swift) and D. Kocevski (NASA/GSFC/ORAU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160601A
78 s after the BAT trigger (Kocevski et al., GCN Circ. 19478
Not found
 
 
).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 19484
Not found
 
 
) is detected in the initial UVOT exposures.
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)       78             227          147      >21.00
white            78      	589          166      >20.90
v               619             639           19      >17.30
b               544             564           19      >18.32
u (fc)          289             539    	     491      >20.19
uvw1            668             688           19      >17.72
uvm2            643             663           19      >17.46
uvw2            595             615           19      >17.87

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).