NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 250911d09h01m51s850985usUT
NOTE: Source region spec. is: 263.75012 -16.85417 4"
NOTE: Used archived XRT position of 263.75012 -16.85417  4.00
NOTE: position reference is GCN_Circulars-41784
NOTE: Possible detection in uu at T+3604.9
NOTE: Possible detection in wh at T+3446.0

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

GRB 250911A: 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 250911A
3446 s after the BAT trigger (Klingler et al., GCN Circ. 41781).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-41784 ***
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          3446         3596          147         >19.2
white             3446         4215          344         >19.9
v                 4426         4625          197         >19.6
b                 3810         4010          197         >19.3
u                 3605         5177          331         >18.6
w1                4835         5035          197         >19.3
m2                4630         4830          197         >20.7
w2                4221         4421          197         >19.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.486 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 250911A: 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 250911A
3446 s after the BAT trigger (Klingler et al., GCN Circ. 41781).
A source consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-41784 ***
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             3446         3596          147         19.86 +/- 0.26
v                 4426         4625          197        >19.6
b                 3810         4010          197        >19.3
u                 3605         5177          331         19.16 +/- 0.21
w1                4835         5035          197        >19.3
m2                4630         4830          197        >20.7
w2                4221         4421          197        >19.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.486 in the direction of the burst
(Schlegel et al. 1998).