NOTE: uvot_fluxes_wget.pl vrs. 2020-11-03a fem at 210913d05h44m57s368228usUT
NOTE: Source region spec. is: 129.89292 79.22153 3"
NOTE: Used archived opt source position of 129.89292  79.22153  3.00
NOTE: position reference is GCN_Circulars-30823
NOTE: Possible detection in uu at T+272.3
NOTE: Possible detection in wh at T+59.8

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

GRB 210912A: Swift/UVOT Upper Limits

N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210912A
60 s after the BAT trigger (Troja et al., GCN Circ. 30820).
No optical afterglow consistent with the optical position
(Hu et al. GCN Circ. 30823)
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            60          209          147         >18.5
u_FC               272          490          214         >18.9
white               60          572          167         >18.6
v                  602          621           19         >17.8
b                  528          547           19         >18.3
u                  272          490          214         >18.9
w2                 577          597           19         >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.027 in the direction of the burst
(Schlegel et al. 1998).


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

GRB 210912A: Swift/UVOT Detection

N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210912A
60 s after the BAT trigger (Troja et al., GCN Circ. 30820).
A source consistent with the optical position
(Hu et al. GCN Circ. 30823)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  08:39:34.27 = 129.89280 (deg.)
    Dec (J2000) = +79:13:17.1  =  79.22141 (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               60          209          147         18.73 +/- 0.08
v                  602          621           19        >17.8
b                  528          547           19        >18.3
u                  272          490          214         19.58 +/- 0.31
w2                 577          597           19        >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.027 in the direction of the burst
(Schlegel et al. 1998).