[AAVSO-HEN] GRB 090813: optical candidate from 1.23m CAHA telescope

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
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TITLE:   GCN CIRCULAR
NUMBER:  9782
SUBJECT: GRB 090813: optical candidate from 1.23m CAHA telescope
DATE:    09/08/13 05:01:48 GMT
FROM:    Javier Gorosabel at IAA-CSIC  <jgu at iaa.es>

J. Gorosabel, V. Terron, M. Fernandez, P. Kubanek, M. Jelinek, A.J.
Castro-Tirado (IAA-CSIC), on behalf of a larger collaboration, report;

We have  carried out  I-band observations of  the XRT position  of GRB
090813  (GCN  9781) with  the  1.23m  telescope  of Calar  Alto.   The 
observations started  at 04:18  UT (437 s  after the GRB  trigger). We
detect an object  with a rough magnitude of I~17 coincident with the XRT
position  no present  on the  DSS. We propose  that object  as the optical
afterglow of GRB 090813.