NOTE: uvot_fluxes_wget.pl vrs. 2020-11-03a fem at 210731d20h17m39s144796usUT
NOTE: Source region spec. is: 255.9871 -37.8434 4"
NOTE: Used archived XRT position of 255.98710 -37.84340  4.00
NOTE: position reference is GCN_Notice
NOTE: Possible detection in m2 at T+1181.4

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

GRB 210731: Swift/UVOT Upper Limits

N. P. M. Kuin (UCL-MSSL) and ***BA*** (***BA INSTITUTION***)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210731
1057 s after the BAT trigger (***Author*** et al., GCN Circ. ????).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Notice ***
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 initial exposures are:

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

v                 1156         5936          270         >99.0
b                 1106         5525          273         >99.0
u                 1081         5320          269         >99.0
w1                1057         5115          274         >99.0
m2                1181         6041          176         >12.0
w2                1132         5731          274         >99.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.629 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 210731: Swift/UVOT Detection

N. P. M. Kuin (UCL-MSSL) and ***BA*** (***BA INSTITUTION***)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210731
1057 s after the BAT trigger (***Author*** et al., GCN Circ. ????).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Notice ***
is detected in the initial UVOT exposures.

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

v                 1156         5936          270        >99.0
b                 1106         5525          273        >99.0
u                 1081         5320          269        >99.0
w1                1057         5115          274        >99.0
m2                1181         1201           19         11.32 +/- 0.04
w2                1132         5731          274        >99.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.629 in the direction of the burst
(Schlegel et al. 1998).