NOTE: uvot_fluxes_wget.pl vrs. 2018-11-07 fem at 191222d03h07m49s940407usUT
NOTE: Source region spec. is: 154.8301 -38.1576 3"
NOTE: Used archived uvot source position of 154.83010 -38.15760  3.00
NOTE: position reference is GCN_Notice
NOTE: A UVOT position was reported in GCN_Notice_Sat_21_Dec_19_20:52:34_UT
NOTE: Possible detection in uu at T+304.0
NOTE: Possible detection in wh at T+91.6

=========== Draft Upper Limit Circular ========

GRB 191221B: Swift/UVOT Upper Limits

N. P. M. Kuin (UCL-MSSL) and S. L. Laha (GSFC/UMBC/CRESST)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 191221B
92 s after the BAT trigger (Laha et al., GCN Circ. 26534).
No optical afterglow consistent with the XRT position
(Laha et al. GCN Circ. 26534)
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            92          241          147         >15.5
u_FC               304          554          246         >12.3
white               92         1009          295         >14.8
u                  304          554          246         >12.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).


=========== Draft Detection Circular ========

GRB 191221B: Swift/UVOT Detection

N. P. M. Kuin (UCL-MSSL) and S. L. Laha (GSFC/UMBC/CRESST)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 191221B
92 s after the BAT trigger (Laha et al., GCN Circ. 26534).
A source consistent with the XRT position
(Laha et al. GCN Circ. 26534)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  10:19:19.16 = 154.82984 (deg.)
    Dec (J2000) = -38:09:29.3  = -38.15814 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).

Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white               92          241          147         15.52 +/- 0.02
u                  304          554          246         12.29 +/- 0.02

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).