NOTE: uvot_fluxes_wget.pl vrs. 2018-01-16 fem at 180404d15h27m44s058580usUT
NOTE: Source region spec. is: 53.39265 -50.21504 3"
NOTE: Used archived uvot source position of  53.39265 -50.21504  3.00
NOTE: position reference is GCN_Circ_22590
NOTE: A UVOT position was reported in GCN_Circ_22590
NOTE: Possible detection in uu at T+294.6
NOTE: Possible detection in wh at T+81.5

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

GRB 180404B: Swift/UVOT Upper Limits

M. H. Siegel (PSU) and S. J. LaPorte (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180404B
82 s after the BAT trigger (LaPorte et al., GCN Circ. 22590).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 22594)
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            82          231          147         >18.5
u_FC               295          544          246         >19.1
white               82         6620          608         >19.7
v                  624         7031          510         >19.5
b                  550         7661          322         >20.2
u                  295         7647          736         >19.8
w1                 674         7442          510         >20.6
m2                1600         7236          413         >20.5
w2                 600         6826          452         >20.2

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).


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

GRB 180404B: Swift/UVOT Detection

M. H. Siegel (PSU) and S. J. LaPorte (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180404B
82 s after the BAT trigger (LaPorte et al., GCN Circ. 22590).
A source consistent with the XRT position
(Beardmore et al. GCN Circ. 22594)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  03:33:34.23 =  53.39262 (deg.)
    Dec (J2000) = -50:12:54.2  = -50.21506 (deg.)
with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits 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               82          231          147         18.70 +/- 0.07
v                  624         7031          510        >19.5
b                  550         7661          322        >20.2
u                  295         1670          343         19.77 +/- 0.21
w1                 674         7442          510        >20.6
m2                1600         7236          413        >20.5
w2                 600         6826          452        >20.2

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).