TITLE:   GCN CIRCULAR
NUMBER:  35374
SUBJECT: GRB 231214A: Swift/UVOT Upper Limits
DATE:    23/12/16 13:23:14 GMT
FROM:    Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and Brivio (INAF-OAB) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 231214A (Fermi GBM Team, GCN Circ. 35334; Kocevski et al., GCN Circ. 35342; Navaneeth et al., GCN Circ. 35348), 442 s after the BAT trigger (Brivio et al., GCN Circ. 35335).
No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 35341) 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 initial exposures are:

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

white              442         4733          382         >20.7
v                  4944          4998           54         >18.1
b                  4329         4528          197         >19.6
u                  4123         4322          197         >19.3
w2                4739         4939          197         >19.5

The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.060 in the direction of the burst (Schlegel et al. 1998).