NOTE: uvot_fluxes_wget.pl vrs. 2023-03-23 fem at 230329d06h14m56s965981usUT
NOTE: Source region spec. is: 291.00765 80.00959 3"
NOTE: Used archived uvot source position of 291.00765  80.00959  3.00
NOTE: position reference is GCN_Circ_33527
NOTE: A UVOT position was reported in GCN_Circ_33527
NOTE: Possible detection in wh at T+114.1
NOTE: Possible detection in uu at T+326.3

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

GRB 230328B: Swift/UVOT Upper Limits

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

The Swift/UVOT began settled observations of the field of GRB 230328B
114 s after the BAT trigger (Gropp et al., GCN Circ. 33527).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 33529)
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           114          264          147         >18.2
u_FC               326          576          246         >18.8
white              114          871          200         >18.4
v                  655          849           39         >17.6
b                  582          774           39         >18.3
u                  326          749          265         >18.9
w1                 705          725           19         >18.5
w2                 805          825           19         >18.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.070 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 230328B: Swift/UVOT Detection

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

The Swift/UVOT began settled observations of the field of GRB 230328B
114 s after the BAT trigger (Gropp et al., GCN Circ. 33527).
A source consistent with the XRT position
(Osborne et al. GCN Circ. 33529)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  19:24:01.88 = 291.00783 (deg.)
    Dec (J2000) = +80:00:34.6  =  80.00962 (deg.)
with an estimated uncertainty of 0.44 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              114          264          147         18.38 +/- 0.05
v                  655          849           39        >17.6
b                  582          774           39        >18.3
u                  326          576          246         19.20 +/- 0.16
w1                 705          725           19        >18.5
w2                 805          825           19        >18.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.070 in the direction of the burst
(Schlegel et al. 1998).