TITLE: GCN CIRCULAR NUMBER: 14196 SUBJECT: GRB 130211A: GROND detection of the afterglow DATE: 13/02/11 09:50:35 GMT FROM: Vladimir Sudilovsky at MPE F. Knust, J. Greiner, and V. Sudilovsky (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 130211A (Swift trigger 548276; Oates et al., GCN 14195) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile). Observations started at 03:45 UT on 11.02.2013, 9 min after the GRB trigger. They were performed at a seeing improving over time from 3" to 1.2", and at an average airmass of 1.0. We find one variable source inside the 4.0" error circle, at coordinates RA (2000.0) = 09:50:08.736 Decl (2000.0) = -42:20:32.64 with an error of 0.3". Based on 1500s exposure in g'r'i'z' and 1200s in JHK started at 06:09 UT, we estimate preliminary AB magnitudes of: g' > 25.3 mag, r' = 23.5 +- 0.1 mag, i' = 22.2 +- 0.1 mag, z' = 21.7 +- 0.1 mag, J = 20.6 +- 0.2 mag, H = 20.1 +- 0.2 mag, and K > 19.5 mag. Given magnitudes are calibrated against GROND zeropoints (g'r'i'z') as well as 2MASS field stars (JHK) and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.53 mag in the direction of the burst (Schlegel et al. 1998). After correcting for the expected foreground extinction, the spectral energy distribution of this source is well-fit by a power-law with slope b~1.4. The reduced flux in g' and r' imply a redshift of z~4.3.