TITLE:   GCN CIRCULAR
NUMBER:  15829
SUBJECT: GRB 140213A: GROND Detection of the Optical/NIR Afterglow
DATE:    14/02/14 01:45:51 GMT
FROM:    Jonny Elliott at MPE/GROND  <jonnyelliott@mpe.mpg.de>

J. Elliott, K. Varela (both MPE Garching), D. A. Kann (TLS Tautenburg),
and J. Greiner (MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 140213A (Swift trigger 586569; Holland et
al., GCN #15825) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at La Silla
Observatory (Chile).

Observations started at 00:25 UT on 14 February 2014, 5 hours after the
GRB trigger, and are continuing. They were performed at an average seeing
of 1.9" and at an average airmass of 1.4.

We find a single point source within the 0.4" Swift-UVOT error circle
reported by Siegel & Holland (GCN #15826) and confirmed by Trotter et al.
(GCN #15828).

Based on the first 4.4 min of total exposures in g'r'i'z' and 4 min in
JHK, we estimate preliminary magnitudes (all in AB) of

g' = 19.7 +/- 0.1 mag,
r' = 19.4 +/- 0.1 mag,
i' = 19.2 +/- 0.1 mag,
z' = 19.1 +/- 0.1 mag,
J  = 18.7 +/- 0.1 mag,
H  = 18.5 +/- 0.1 mag, and
K  = 18.4 +/- 0.1 mag.

The spectral energy distribution is best-fit by a straight power-law with
spectral slope b = 0.8 +/- 0.1.

Given magnitudes are calibrated against GROND zeropoints as well as 2MASS
field stars and are not corrected for the expected Galactic foreground
extinction corresponding to a reddening of E_(B-V)=0.07 mag in the
direction of the burst (Schlegel et al. 1998).