NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 250810d00h55m41s558143usUT
NOTE: Source region spec. is: 233.00042 -53.29625 4"
NOTE: Used archived XRT position of 233.00042 -53.29625  4.00
NOTE: position reference is GCN_Circulars-41304
NOTE: Possible detection in bb at T+534.2 sum
NOTE: Possible detection in vv at T+434.7
NOTE: Possible detection in uu at T+809.3 sum

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

GRB 250809A: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) and T. M. Parsotan (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250809A
128 s after the BAT trigger (Parsotan et al., GCN Circ. 41303).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-41304 ***
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

u_FC               128          378          246         >19.1
v                  435          755           58         >17.1
b                  384         1038           97         >18.4
u                  128         1013          452         >19.0
w1                 484          805           58         >18.4
m2                 459          780           58         >20.1
w2                 410         1064           78         >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.919 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 250809A: Swift/UVOT Detection

***UBS*** (***INSTITUTION***) and T. M. Parsotan (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250809A
128 s after the BAT trigger (Parsotan et al., GCN Circ. 41303).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-41304 ***
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                  435          755           58         17.62 +/- 0.21
b                  384         1038           97         18.86 +/- 0.19
u                  128         1013          452         19.57 +/- 0.21
w1                 484          805           58        >18.4
m2                 459          780           58        >20.1
w2                 410         1064           78        >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.919 in the direction of the burst
(Schlegel et al. 1998).