NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 250502d08h55m19s662761usUT
NOTE: Source region spec. is: 233.38612 -18.11783 4"
NOTE: Used archived XRT position of 233.38612 -18.11783  4.00
NOTE: position reference is GCN_Circulars-40292
NOTE: Possible detection in w1 at T+1244.7 sum
NOTE: Possible detection in wh at T+843.0
WARNING: t_start for light curve (118) and t_start from the exposure report (139) do not agree.
  Replace ??? in draft Circular with correct value.

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

GRB 250430A: 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 250430A
***???*** s after the BAT trigger (Parsotan et al., GCN Circ. 40292).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-40292 ***
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           843          993          147         >19.6
white              843         1856          245         >19.9
v                  118         1733           52         >18.6
b                 1122         1831           97         >19.6
u                  794         1807          117         >18.7
w1                 424         1783          156         >18.8
m2                1393         1413           19         >18.7
w2                 696         1364           58         >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.092 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 250430A: 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 250430A
***???*** s after the BAT trigger (Parsotan et al., GCN Circ. 40292).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-40292 ***
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  15:33:32.93 = 233.38720 (deg.)
    Dec (J2000) = -18:07:06.1  = -18.11836 (deg.)
with an estimated uncertainty of 0.47 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              843         1166          167         20.17 +/- 0.20
v                  118         1733           52        >18.6
b                 1122         1831           97        >19.6
u                  794         1807          117        >18.7
w1                 424         1265           97         18.98 +/- 0.31
m2                1393         1413           19        >18.7
w2                 696         1364           58        >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.092 in the direction of the burst
(Schlegel et al. 1998).