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GCN Circular 8420

GRB 081025: TLS upper limits
2008-10-28T00:28:59Z (16 years ago)
Alexander Kann at TLS Tautenburg <>
D. A. Kann, S. Schulze, C. Hoegner, S. Klose (TLS Tautenburg) and J. 
Greiner (MPE Garching) report:

We observed the BAT Slew GRB 081025 (A. Copete et al., GCN 8409) with the 
TLS Tautenburg 1.34m Schmidt telescope. Observations were initialized in 
RRM mode (S. Klose et al., GCN 3609) as the BAT_SLEW_POSITION had been 
received at dusk. After obtaining 2 x 120 sec Ic-band images, we realized 
the large time delay and switched to deeper imaging. We further obtained 2 
x 600 sec Ic-band images and one 600 sec Rc-band image.

At the position of the X-ray afterglow candidate (J. Mao et al., GCN 
8411), we do not detect any source. We find the following upper limits in 
comparison with the USNOB1.0 star at (catalog position, J2000) R.A. = 
16:21:28.125, Dec. = +60:28:42.35, which has R2 = 18.61, I = 17.84:

dt	exp		Filter	upper limit (2 sigma)

0.38672	2x120+2x600	Ic	21.5

0.40047	1x600		Rc	22.5

These limits are in agreement with the g-band limit of Khamitov et al. 
(GCN 8418).

We point out the existence of the galaxy cluster NSC 2162144+602602 at 
z=0.3903 (accoriding to SIMBAD) to the southeast of the afterglow 
position. The nearest galaxy (about 100" distant) seems to be a massive 
elliptical, possible a cD galaxy.

No further observations are planned.

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