TITLE:   GCN CIRCULAR
NUMBER:  11246
SUBJECT: GRB 100901A: TLS Detection at 5.5 days
DATE:    10/09/07 05:13:41 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, F. Ludwig and B. Stecklum (TLS Tautenburg) report:

We observed the afterglow of the Swift GRB 100901A (Immler et al., GCN
11159) with the TLS 1.34m Schmidt telescope under excellent conditions in
the fifth night. We obtained 3 x 600 sec images in Rc, the afterglow is
faintly visible in each single image and well-detected in the stack.
Calibration against the SDSS (Kann et al., GCN 11236) yields Rc = 21.91
+/- 0.11 at 5.550556 days after the GRB. This is somewhat subluminous
compared to the extrapolation of the earlier decay (Kann et al., GCN
11236) but only further deep observations can confirm if another break has
occured.

Further observations are improbably due to upcoming inclement weather.

This message may be cited.