NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 250424d13h36m44s268484usUT
NOTE: Source region spec. is: 217.49998 -35.02518 3"
NOTE: Used archived uvot source position of 217.49998 -35.02518  3.00
NOTE: position reference is GCN_Circ_40224
NOTE: A UVOT position was reported in GCN_Circ_40224
NOTE: Possible detection in w1 at T+1602.4 sum
NOTE: Possible detection in wh at T+254.5
NOTE: Possible detection in bb at T+1135.2 sum
NOTE: Possible detection in uu at T+657.5 sum

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

GRB 250424A: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250424A
254 s after the BAT trigger (Cenko et al., GCN Circ. 40224).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-40232 ***
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           254          404          147         >18.8
white              254         1869          431         >19.0
v                  411         1918          175         >18.7
b                  509         1844          136         >19.3
u                  485         1820          156         >18.6
w1                 460         1795          156         >18.7
m2                 436         1598           97         >18.4
w2                 559         1894          156         >19.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.064 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 250424A: Swift/UVOT Detection

***UBS*** (***INSTITUTION***) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250424A
254 s after the BAT trigger (Cenko et al., GCN Circ. 40224).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-40232 ***
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  14:29:60.00 = 217.49998 (deg.)
    Dec (J2000) = -35:01:30.6  = -35.02518 (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              254          404          147         18.96 +/- 0.07
v                  411         1918          175        >18.7
b                  509         1844          136         19.97 +/- 0.26
u                  485         1647          136         19.15 +/- 0.20
w1                 460         1795          156         19.44 +/- 0.31
m2                 436         1598           97        >18.4
w2                 559         1894          156        >19.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.064 in the direction of the burst
(Schlegel et al. 1998).