TITLE:   GCN CIRCULAR
NUMBER:  23894
SUBJECT: GRB 190211A: Swift/UVOT Detection
DATE:    19/02/12 18:05:47 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190211A
203 s after the BAT trigger (Marshall et al., GCN Circ. 23883).
A source consistent with the optical position
(Xu et al. GCN Circ. 23884) and just outside the
90% confidence XRT position (Evans et al. GCN Circ. 23888)
is detected in the only UVOT exposure.

The preliminary UVOT position is:
     RA  (J2000) =  13:06:38.45 =  196.66019 (deg.)
     Dec (J2000) = +41:58:04.9  =  41.96803 (deg.)
with an estimated uncertainty of 0.53 arc sec. (radius, 90% confidence).

The preliminary detection using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early
exposures is:
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              203          351          146         19.73 +/- 0.11

The magnitude in the table is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).