[vsnet-grb-info 8569] GRB 091024: TLS Upper Limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10077
SUBJECT: GRB 091024: TLS Upper Limit
DATE:    09/10/25 05:59:03 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann at tls-tautenburg.de>

D. A. Kann, and U. Laux (TLS Tautenburg) report:

We observed the afterglow of the ultra-long Swift/GBM GRB 091024 (Marshall 
et al., GCN 10062, Mundell et al., GCN 10063, Bissaldi & Connaughton, GCN 
10070) with the 1.34m Schmidt telescope of the Thueringer

Landessternwarte Tautenburg, Germany, 0.6 days after the GRB. We obtained 
6 x 600 sec images in Rc.

As a comparison star, we use the USNOB1.0 star at:

RA (J2000) =    22:37:31.11
Dec. (J2000) = +56:59:26.23

which has R2 = 17.78 mag. This was one of the rare non-blended stars that 
was bright enough to be detected in the catalog.

At the afterglow position, we do not detect any source which is not 
detected anyway in the DSS2 red plate. We place the following 2 sigma 
upper limit on the afterglow:

dt		Filter	UL
____________________________________
0.602309	Rc	21.0

and note that the true upper limit may be less deep due to crowding (the 
afterglow pretty much conincides with a ~20th mag object detected in the 
DSS).

No further observations are planned.

This message may be cited.