GCN Circular 14031

T. Kruehler (DARK/NBI), S. Klose (TLS Tautenburg) and J. Greiner (MPE Garching) 
report on behalf of the GROND team:

We observed the field of the Swift GRB 121201A (Yershov et al., GCN 14025
Not found
 
 
) 
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) 
mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile).

Observations started on December 02, 2012, 00:28 UT which is roughly
12.0 hr after the trigger. We clearly detect the afterglow of 
GRB 121201A (Yershov et al., GCN 14025
Not found
 
 
) in the optical filters, 
but not in the NIR bands. Based on stacked images at
a mid-time of 01:05 UT with an effective integration time of 25 min
in g'r'i'z' and 20 min in JHKs, we estimate preliminary AB magnitudes and 
upper limits of:

g' = 24.2 +- 0.2 
r' = 23.0 +- 0.1
i' = 22.7 +- 0.1
z' = 22.5 +- 0.1
J > 21.5
H > 21.0
Ks > 19.9

These magnitudes and upper limits are calibrated against SDSS standards 
in the optical, and 2MASS field stars in the NIR bands. After correcting 
for the Galactic extinction corresponding to a reddening of E(B-V)=0.01
(Schlegel et al. 1998),  a fit to this SED returns a photometric redshift of 3.6 +0.2 -0.3.