[vsnet-grb-info 20343] GRB 180222A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22439
SUBJECT: GRB 180222A: Swift/UVOT Upper Limits 
DATE:    18/02/23 20:49:37 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel at swift.psu.edu>

S. A. Sebzda (PSU) 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 180222A
83 s after the BAT trigger (Cannizzo et al., GCN Circ. 22433).
No optical afterglow consistent with the XRT position
(Cannizzo et al. GCN Circ. 22433)
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            83          233          147         >20.6
u_FC               295          545          246         >19.5
white               83         1196          353         >21.6
v                  624         1073           58         >18.0
b                  551         1171           58         >18.6
u                  295         1146          285         >19.7
w1                 673         1122           58         >18.0
m2                 649         1097           58         >18.0
w2                 600         1221           78         >19.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.68 in the direction of the burst
(Schlegel et al. 1998).