NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 250808d09h10m47s834433usUT
NOTE: Source region spec. is: 51.44829 -47.88782 3"
NOTE: Used archived uvot source position of  51.44829 -47.88782  3.00
NOTE: position reference is GCN_Circ_41262
NOTE: A UVOT position was reported in GCN_Circ_41262
NOTE: Possible detection in wh at T+111.2
NOTE: Possible detection in uu at T+323.2

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

GRB 250807A: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) and N. J. Klingler (GSFC/UMBC/CRESSTII)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250807A
111 s after the BAT trigger (Klingler et al., GCN Circ. 41262).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-41270 ***
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           111          261          147         >17.9
u_FC               323          573          246         >18.9
white              111         1719          411         >18.8
v                  653         1769          136         >19.1
b                  579         1695          117         >19.3
u                  323         1841          361         >19.3
w1                 702         1818          117         >19.0
w2                 801          821           19         >18.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.011 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 250807A: Swift/UVOT Detection

***UBS*** (***INSTITUTION***) and N. J. Klingler (GSFC/UMBC/CRESSTII)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250807A
111 s after the BAT trigger (Klingler et al., GCN Circ. 41262).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-41270 ***
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  03:25:47.60 =  51.44832 (deg.)
    Dec (J2000) = -47:53:16.0  = -47.88777 (deg.)
with an estimated uncertainty of 0.43 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              111          261          147         17.99 +/- 0.04
v                  653         1769          136        >19.1
b                  579         1695          117        >19.3
u                  323          573          246         19.32 +/- 0.15
w1                 702         1818          117        >19.0
w2                 801          821           19        >18.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.011 in the direction of the burst
(Schlegel et al. 1998).