[vsnet-grb-info 17650] GRB 160225A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19087
SUBJECT: GRB 160225A: Swift/UVOT Upper Limits
DATE:    16/02/26 05:10:10 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel at swift.psu.edu>

M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160225A
839 s after the BAT trigger (Siegel et al., GCN Circ. 19075).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 19077) or the previously reported
optical position (Wierema, et al., GCN Circ. 19082) 
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           839          989          147         >20.7
white              839         2657          342         >21.1
v                 1121         2708          194         >19.9
b                 1047         2632          194         >20.8
u                 1022         2608          156         >19.9
w1                 998         3036          311         >20.1
m2                1494         2912          236         >20.2
w2                1446         2683           78         >20.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).