[vsnet-grb-info 24505] GRB 191228A: ePESSTO+ NTT optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26604
SUBJECT: GRB 191228A: ePESSTO+ NTT optical upper limit
DATE:    19/12/28 10:11:51 GMT
FROM:    Daniele B Malesani at DTU Space  <malesani at space.dtu.dk>

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).