TITLE:   GCN CIRCULAR
NUMBER:  35534
SUBJECT: GRB 240112C: Swift/UVOT Detection
DATE:    24/01/14 18:22:22 GMT
FROM:    Paul Kuin at MSSL <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and Eyles-Ferris (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240112C
121 s after the BAT trigger (Eyles-Ferris et al., GCN Circ. 35522).
A source consistent with the XRT position is detected in the initial
UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  18:02:34.58 = 270.64410 (deg.)
    Dec (J2000) = +24:29:21.3  =  24.48925 (deg.)
with an estimated uncertainty of 0.43 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              121          236          113         16.98 +/- 0.04
v                 4955         5126          169        >18.6
b                 4340         4539          197         19.35 +/- 0.16
u                 4134         4334          197         19.11 +/- 0.18
w1                3930         4129          197         19.13 +/- 0.24

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.108 in the direction of the burst
(Schlegel et al. 1998).