[vsnet-grb-info 25339] GRB 200324A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27439
SUBJECT: GRB 200324A: Swift/UVOT Upper Limits
DATE:    20/03/25 12:48:41 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld at ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and S. Dichiara (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 200324A 215 s after the BAT trigger 
(Dichiara et al., GCN Circ. 27428).
No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 27430)
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           215          365          147         >21.0
u_FC               374          624          246         >20.6
white              215         1376          373         >21.7
v                  704         1427           78         >18.9
b                  630         1527           97         >19.8
u                  374         1327          304         >20.2
w1                 754         1477           78         >19.1
w2                1381         1401           19         >19.1

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).