TITLE:   GCN CIRCULAR
NUMBER:  1894
SUBJECT: Possible break in the GRB 030226 light curve
DATE:    03/02/27 08:55:44 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

J. Greiner (MPE Garching),
C. Ries, H. Barwig (Uni. Munich),
J. Fynbo (Uni Aarhus),
S. Klose (TLS Tautenburg),
on behalf of the GRACE collaboration

report:

We observed the afterglow of the HETE burst (H10893; Suzuki et al., GCN 1888) 
GRB 030226 (Fox et al., GCN 1879; Price et al., GCN 1880) in the R band
with the EMMI and SUSI instruments at the NTT (La Silla, ESO) and the MONICA
imager at the Wendelstein 0.8 m telescope (Germany). We calibrated against
the USNO-B R2 magnitudes of 5 surrounding stars which provides basically
the same calibration as that given for stars A and B by Garnavich et al. 
(GCN 1885; R=15.39 +/-0.05 and R=17.06 +/-0.05, respectively). A preliminary
reduction gives the following magnitudes:

                 Start time    exposure      OT         star A        star B
NTT/EMMI       Feb 26 08:27   3x300 s   18.80+-0.07   15.40+-0.05   17.05+-0.05
Wendelstein    Feb 26 19:04   2x600 s   19.87+-0.10   15.47+-0.08   17.05+-0.10
Wendelstein    Feb 27 03:12     600 s   20.60+-0.13   15.42+-0.08   17.04+-0.10
Wendelstein    Feb 27 03:23     600 s   20.74+-0.13   15.43+-0.08   17.05+-0.10
NTT/SUSI       Feb 27 05:25   3x180 s   21.00+-0.20   15.47+-0.10      ---

We confirm the decay slope of -0.88 as communicated by Price & Warren
(GCN 1890) until about 0.8 days after the GRB. Thereafter, the brightness
seems to drop significantly faster. A light curve plot will be available
at http://www.mpe.mpg.de/~jcg/grb030226.html. Further monitoring is strongly 
encouraged.

We are grateful for the assistence of the staff at La Silla and Wendelstein.