[vsnet-grb-info 26667] GRB 200901A: FRAM-Auger optical limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28767
SUBJECT: GRB 200901A: FRAM-Auger optical limit
DATE:    20/10/24 08:57:10 GMT
FROM:    Martin Jelinek at Astro.Inst-AVCR,Ondrejov  <martin.jelinek at asu.cas.cz>

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

report:

The 30cm robotic telescope FRAM-Auger in Malargue (Argentina)
reacted robotically to the Swift/BAT alert of GRB200901A
(Simpson et al., GCNC 28335, Burrows et al., GCNC 28336,
Kennea et al., GCNC 28341, and Breeveld et al., GCNC 28342).

The weather was cloudy but as the clouds moved, we could
select some good images, in particular there is a continuous
set of 14 exposures between 4:00 and 4:17 UT, where the
position could be well identified.

We do not detect any new or strongly variable source at or
around the reported X-ray errorbox at single frames or a
combined 14 x 20s R-band image with the exposure mid-time
21.3 min after the initial trigger. The combined exposure has
a limiting magnitude R(Vega) = 17.8, as calibrated against
the Atlas Catalogue.