[AAVSO-HEN] GRB 091018: BOOTES-3 observations

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  10043
SUBJECT: GRB 091018: BOOTES-3 observations
DATE:    09/10/19 19:49:59 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte at iaa.es>

A. de Ugarte Postigo (INAF-OAB), P. Kubanek (U. Valencia, IAA-CSIC),
M. Jelinek, A.J. Castro-Tirado, J. Gorosabel, R. Cunniffe, S. Guziy  
(IAA-CSIC),
B.A. Allen (Vintage Lane Obs.) and P. Yock (Auckland Univ.) report:

We have observed the afterglow of GRB 091018 (Stamatikos et al. CGN
10034) with the 0.6m Yock-Allen telescope (BOOTES-3) located in
Blenheim (New Zealand). A combination of 21x30s unfiltered images with
mean epoch Oct. 19.625 UT (18.2 hours after the burst) shows the  
afterglow
at a magnitude of R=20.0+/-0.3. The photometry has been obtained using
as comparison 5 USNO-B1.0 stars. This magnitude implies a rough
decay slope of alpha = 0.7 +/- 0.2 (with F ~ t^(-alpha)) as compared to
the values of Filgas et al. (GCN 10039). Further analysis is ongoing.