TITLE:   GCN CIRCULAR
NUMBER:  17617
SUBJECT: GRB150323A: Swift-UVOT detection of the afterglow
DATE:    15/03/23 11:40:56 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and Amaral-Rogers (U Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150323A
156 s after the BAT trigger (Amaral-Rogers et al., GCN Circ. 17611).
A weak optical afterglow consistent with the XRT position (Goad et al.,
GCN Circ. 17615) or the P60 position (GCN Circ. 17612) is be present
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           156          306          147         20.53+/-0.30
u_FC               314          564          246         >20.0
white             4066         5702         1635         20.96+/-0.33
v                 5912         6112          197         18.93+/-0.29
u                  314         5291          442         >20.7
u                 4991         5191          197         19.86+/-0.35
w1                4887         5086          197         >20.2
m2                4682         4881          197         >20.9
w2                4272         4472          197         >20.4

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).