[AAVSO-HEN] GRB 080205: OA evolution from KAIT observations

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TITLE:   GCN CIRCULAR
NUMBER:  7254
SUBJECT: GRB 080205: OA evolution from KAIT observations 
DATE:    08/02/05 16:25:04 GMT
FROM:    Alex Filippenko at UC Berkeley  <alex at astro.berkeley.edu>

W. Li, D. Perley, and  A. V. Filippenko, University of California, 
Berkeley, on behalf of the KAIT GRB team, report:

We report further analysis of the KAIT observations of GRB 080205
(Swift Trigger 302506; Markwardt et al. GCN 7250) announced by
Li et al. (GCN 7251).  Preliminary reduction of the unfiltered 
data shows that the optical afterglow (OA) has a nearly constant 
brightness of mag 18.1 from t = 65 s to 90 s, declines to mag 19.1 
by t = 171 s, rises to mag 16.9 by t = 537 s, and has a steep 
power-law decline (with index around -1.6) thereafter until
at least t = 50 min. The OA is also detected in multiple I-band 
and V-band images, suggesting that the redshift of the GRB is lower 
than roughly 4 or 5.  The overall behavior of the OA of GRB 080205 
is similar to that of GRB 060206 (Monfardini et al. 2006, ApJ, 
648, 1125).

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