[vsnet-grb-info 9702] GRB 100901A - NOT optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11170
SUBJECT: GRB 100901A - NOT optical observation
DATE:    10/09/02 03:09:25 GMT
FROM:    Annalisa De Cia at U of Reykjavik,Science Inst.  <annalisa at raunvis.hi.is>

A. De Cia, P.M. Vreeswijk and P. Jakobsson (University of
Iceland) report:

We observed the field of GRB 100901A (Immler et al., GCN 11159)
with the NOT equipped with ALFOSC in good weather conditions.
Observations were carried out in the R filter for 15 minutes,
with mean time 12.13 hours after the GRB trigger.

We measure R=17.3 for the afterglow, not corrected for Galactic
extinction, calibrated against the USNO-B1.0 1127-0027231
reference star (R=15.37) used by Andreev et al., GCN 11166 and
GCN 11168.

 time after trigger       exposure (s)         R mag

     12.13 hours            3 x 300             17.3

We acknowledge the careful assistence of the NOT staff, in
particular Tapio Pursimo.