NOTE: uvot_fluxes_wget.pl vrs. 2020-10-16a fem at 201020d13h07m54s885682usUT
NOTE: Source region spec. is: 261.22779 31.42834 3"
NOTE: Used archived uvot source position of 261.22779  31.42834  3.00
NOTE: position reference is GCN_Circ_28696
NOTE: A UVOT position was reported in GCN_Circ_28696
NOTE: Possible detection in uu at T+302.3
NOTE: Possible detection in wh at T+144.3
NOTE: Possible detection in vv at T+805.4

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

GRB 201020A: Swift/UVOT Upper Limits

M. H. Siegel (PSU) and Ambrosi (INAF-IASFPA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 201020A
144 s after the BAT trigger (Ambrosi et al., GCN Circ. 28696).
No optical afterglow consistent with the XRT position
(Ambrosi et al. GCN Circ. 28696)
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           144          294          147         >18.1
u_FC               302          552          246         >19.3
white              144          774          186         >18.2
v                  632          825           39         >17.4
b                  558          750           39         >19.3
u                  302          725          265         >19.4
w1                 681          875           39         >19.8
m2                 656          676           20         >18.3
w2                 608          800           39         >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 201020A: Swift/UVOT Detection

M. H. Siegel (PSU) and Ambrosi (INAF-IASFPA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 201020A
144 s after the BAT trigger (Ambrosi et al., GCN Circ. 28696).
A source consistent with the XRT position
(Ambrosi et al. GCN Circ. 28696)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  17:24:54.66 = 261.22773 (deg.)
    Dec (J2000) = +31:25:42.1  =  31.42837 (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              144          294          147         18.19 +/- 0.05
v                  632          825           39         18.00 +/- 0.24
b                  558          750           39        >19.3
u                  302          552          246         19.84 +/- 0.21
w1                 681          875           39        >19.8
m2                 656          676           20        >18.3
w2                 608          800           39        >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).