TITLE:   GCN CIRCULAR
NUMBER:  25794
SUBJECT: GRB 190919B: FRAM-Auger optical detection
DATE:    19/09/20 15:00:30 GMT
FROM:    Martin Jelinek at Astro.Inst-AVCR,Ondrejov  <martin.jelinek@asu.cas.cz>

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

report:

The 30 cm robotic telescope FRAM-Auger in Malargue (Argentina)
reacted robotically to the INTEGRAL/IBAS alert of GRB190919B
(Mereghetti et al., GCNC 25788), starting with a series of 20 s
unfiltered images at 23:47:16 UT, i.e. 36 s post trigger.

We clearly detect the optical afterglow reported by Bolmer (GCN
25789), Tyurina et al. (GCN 25791) and Pugliese et al. (GCN
25792) at single frames. The optical lightcurve seems to have
a multi-peak structure with maxima reaching r'(AB) ~ 16.5 mag,
and fades beyond the single-image detection limit of r' ~ 17.2 by
~ 10 minutes post trigger. A detailed analysis is ongoing.