TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  829
SUBJECT: GRB 000926, Optical Decay
DATE:    00/10/03 18:37:24 GMT
FROM:    Jules Halpern at Columbia U.  <jules@astro.columbia.edu>

J. P. Halpern, N. Mirabal (Columbia U.), D. Turnshek
& J. Busche (U. Pittsburgh) report on behalf of the 
MDM Observatory GRB follow-up team:

"Using the MDM 2.4m, we obtained 5x900 s exposures in the
R band centered on Oct. 2.16 UT.  Using the comparison star
previously measured at R = 17.06 (GCN #824), we find for the
OT R = 23.17 +/- 0.09 (1 sigma).  This is significantly fainter
than the measurement made by Veillet just after ours (GCN #827,
R = 22.82 +/- 0.08 on Oct. 2.26), which constitutes an interesting
discrepancy.  Our own measurement is consistent with a constant
decay slope alpha = -2.23 +/- 0.07 after day 2, and would predict
that R = 23.9 +/- 0.1 on Oct. 4.0 UT.

This image and an updated decay curve are posted at
http://www.astro.columbia.edu/~jules/grb/000926

This message may be cited."

[GCN OPS NOTE 03oct00:  At the author's request the value for the alpha
value was changed from the original value of -2.33 to -2.23.  The original
value was a typo.]