NOTE: uvot_fluxes_wget.pl vrs. 2018-01-16 fem at 180620d23h01m13s715299usUT
NOTE: Source region spec. is: 279.89619 23.24419 3"
NOTE: Used archived uvot source position of 279.89619  23.24419  3.00
NOTE: position reference is GCN_Circ_22805
NOTE: A UVOT position was reported in GCN_Circ_22805
NOTE: Possible detection in uu at T+500.0
NOTE: Possible detection in wh at T+270.3
NOTE: Possible detection in bb at T+524.7
NOTE: Possible detection in w1 at T+475.8
NOTE: Possible detection in vv at T+426.7
NOTE: Possible detection in w2 at T+1893.6 sum
NOTE: Possible detection in m2 at T+1598.2 sum

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

GRB 180620A: Swift/UVOT Upper Limits

A. A. Breeveld (UCL-MSSL) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180620A
270 s after the BAT trigger (Evans et al., GCN Circ. 22798).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 22802)
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           270          420          147         >17.6
white              270         7930          861         >18.6
v                  427         8342          607         >18.8
b                  525         7726          573         >19.4
u                  500         7521          411         >18.4
w1                 476         7316          410         >18.4
m2                 623         8495          536         >19.2
w2                 574         8136          588         >19.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.13 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 180620A: Swift/UVOT Detection

A. A. Breeveld (UCL-MSSL) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180620A
270 s after the BAT trigger (Evans et al., GCN Circ. 22798).
A source consistent with the XRT position
(Osborne et al. GCN Circ. 22802)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  18:39:35.09 = 279.89619 (deg.)
    Dec (J2000) = +23:14:39.1  =  23.24419 (deg.)
with an estimated uncertainty of 0.43 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              270          420          147         17.65 +/- 0.04
v                  427         1073           78         18.16 +/- 0.20
b                  525          717           39         18.70 +/- 0.19
u                  500          520           19         17.58 +/- 0.20
w1                 476         2158          194         18.80 +/- 0.19
m2                 623         8495          536         19.80 +/- 0.26
w2                 574         8136          588         19.89 +/- 0.21

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.13 in the direction of the burst
(Schlegel et al. 1998).