Tomas Mueller (Southampton), Juanita Antilen (Universidad de Chile),
Daniele B. Malesani (DTU Space), Paolo D'Avanzo (INAF/Brera), Joe
Anderson (ESO), Mariusz Gromadzki (Warsaw), Cosimo Inserra (Cardiff),
Erkki Kankare (Turku), Matt Nicholl (Birmingham), Ofer Yaron (Weizmann),
David Young (QUB), Roberta Carini (INAF/Roma), Regis Cartier (CTIO),
Ting-Wan Chen (Stockholm), Matt Grayling, Mat Smith, Phil Wiseman
(Southampton), Chris Frohmaier (ICG Portsmouth), report:
We observed GRB 191228A (Bernardini et al., GCN 26601) under the the
extended Public ESO Spectroscopic Survey for Transient Objects
(ePESSTO+; see Smartt et al. 2015, A&A, 579, 40 http://www.pessto.org ).
The observations were performed on the ESO New Technology Telescope at
La Silla with the EFOSC2 instrument in imaging mode, starting on 2019
Dec 28 at 01:22:23 UT (i.e. 1.35 hr after the burst).
In a 2-minute image taken using the r filter, we detect no objects
consistent with the XRT position, down to a 3-sigma limiting magnitude
of r = 22.6 AB (calibrated against stars from the Pan-STARRS catalog).