TITLE:   GCN CIRCULAR
NUMBER:  32873
SUBJECT: GRB 221027B: FRAM-ORM and Ondrejov SBT optical limits
DATE:    22/10/28 12:45:08 GMT
FROM:    Martin Jelinek at Astro.Inst-AVCR,Ondrejov  <martin.jelinek@asu.cas.cz>

Martin Jelinek, Jan Strobl, Rene Hudec and Cyril Polasek
(ASU CAS Ondrejov, CZ),
Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek,
Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza
(Institute of Physics, Prague, CZ)

report:

The 2x20cm robotic telescope BART-SBT in Ondrejov (CZ) reacted robotically
to the Swift alert of GRB221027B (Lien et al., GCNC 32867 and Perri et al.
GCNC 32870, GCNC 29119 and 29124), obtaining a series of 12s unfiltered
frames at 19:19:46 UT, i.e. 367s post trigger.

The 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted to the same
alert, providing a series of 60s unfiltered images from 19:28:20 UT, i.e.
882s post trigger.

Similarly to Hu et al. (GCNC 32869) and Lipunov et al. (GCNC 32871), we do
not detect any new or strongly variable source neither in single or in
combined frames with the following limits:

Tel.    T-T0[mid,s]  Texp[s]  Limit[ABmag]  Note
SBT     374          12       <15.5         (similar during the following
30 min)
SBT     494          240      <17.0
SBT     674          600      <17.3
SBT     1574         2400     <17.7
FRAM    912          60       <17.0         (similar next 60 minutes)
FRAM    1238         10x60    <18.0