[vsnet-grb-info 1887] GRB 050801: ROTSE-III Early Afterglow Break

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3726
SUBJECT: GRB 050801: ROTSE-III Early Afterglow Break 
DATE:    05/08/01 19:50:15 GMT
FROM:    Eli Rykoff at U of Michigan/ROTSE  <erykoff at umich.edu>

E.S. Rykoff (U Mich), S.A. Yost (U Mich), W. Rujopakarn (U Mich), H. 
Swan (U Mich), K. Alatalo (Berkeley), R. Quimby (U Texas) report on 
behalf of the ROTSE collaboration:

ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, is 
observing the optical counterpart to GRB 050801 (Swift trigger 148522, 
Band et al, GCN 3725).  The early afterglow reported in GCN 3723 is 
characterized by a broken power-law, which does not decay significantly 
from t+21s to t+200s, followed by a decline with a power law index of 
~-1.1.  Our preliminary photometry, relative to the USNO A2.0 catalog, 
also shows some possible sub-structure to the lightcurve.

tstart-tburst  exptime        mag
---------------------------------
  21.8          5.0        14.99+/-0.06
  203.0         20.0       15.01+/-0.03
  1590.3        60.0       17.29+/-0.15