TITLE:   GCN CIRCULAR
NUMBER:  42959
SUBJECT: GRB251129A/EP251129a: Swift UVOT detection
DATE:    25/12/02 18:31:14 GMT
FROM:    Paul Kuin at MSSL <npkuin@gmail.com>

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

The Swift/UVOT began observations of the field of GRB 251129A  16.8 ks
after the SVOM  trigger (Tan et al., GCN Circ. 42877). GRB251129A was
also  detected
by the EP (Wu et al, GCN Circ. 16828).
The optical afterglow consistent with the  SVOM/COLIBRI position (Angulo et
al. GCN Circ. 42880; Watson, GCN Circ. 42883)  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) are::

Filter   T_start(s)  T_stop(s)  Exp(s)     Mag

white    16828         17147     315    19.63 +/- 0.07
white    27564        28089     502    19.69 +/- 0.12
white   111007       117142    1044    20.22 +/- 0.12
white   227072       234439    2745    20.92 +/- 0.17
u        16503                   16823           315          20.06  +/-
0.30

The magnitudes in the table are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.025 in the direction of the burst (Schlegel
et al. 1998).