NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 250516d17h53m29s059744usUT
NOTE: Source region spec. is: 334.60979 -9.11950 4"
NOTE: Used archived XRT position of 334.60979  -9.11950  4.00
NOTE: position reference is GCN_Circulars-40468
NOTE: Possible detection in wh at T+108.3

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

GRB 250516A: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) and A. P. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250516A
108 s after the BAT trigger (Beardmore et al., GCN Circ. 40467).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-40468 ***
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           108          258          147         >19.5
u_FC               320          570          246         >19.6
white              108         1715          411         >19.9
v                  650         1765          136         >18.2
b                  576         1691          117         >19.2
u                  320         1838          362         >19.9
w1                 699         1814          117         >18.6
w2                 626         1741           97         >19.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.062 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 250516A: Swift/UVOT Detection

***UBS*** (***INSTITUTION***) and A. P. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250516A
108 s after the BAT trigger (Beardmore et al., GCN Circ. 40467).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-40468 ***
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

white              108         1024          334         20.31 +/- 0.18
v                  650         1765          136        >18.2
b                  576         1691          117        >19.2
u                  320         1838          362        >19.9
w1                 699         1814          117        >18.6
w2                 626         1741           97        >19.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.062 in the direction of the burst
(Schlegel et al. 1998).