TITLE:   GCN CIRCULAR
NUMBER:  17057
SUBJECT: GRB 141109A: Swift/UVOT Detection
DATE:    14/11/10 22:55:16 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 141109A
139 s after the BAT trigger (D'Avanzo et al., GCN Circ. 17037).
A source consistent with the optical position (Covino, GCN Circ. 17039;
Xu et al., GCN Circ. 17040) is detected in the initial UVOT exposures.

The 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              139          289          147         20.0 +/- 0.2
white             3991         4191          197         20.8 +/- 0.2
v                 5656         5856          197        >18.9
b                 3786         3986          197        >20.3
u                  297         6276          227        >19.7
w1                6066         6266          197        >20.1
m2                5861         6061          197        >20.7
w2                4197         4339          140        >20.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).