[vsnet-grb-info 15100] GRB 140614A: GROND afterglow candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16392
SUBJECT: GRB 140614A: GROND afterglow candidate
DATE:    14/06/14 02:49:55 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose at tls-tautenburg.de>

M. Tanga (MPE Garching), T. Kruehler (ESO, Santiago), S. Klose, D. A. Kann 
(both TLS Tautenburg), and J. Greiner (MPE Garching) report:

We observed the field of GRB 140614A (Swift trigger 601646; Page et al., 
GCN 16391) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, 
PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla 
Observatory (Chile).

Observations started at 01:09:27 UT on June 14, about 5 min after the GRB 
trigger. They were obtained at airmass 1.5 and a seeing of 2". Inside the 
X-ray error circle we detect a source at coordinates RA, DEC (J2000) = 
15:24:40.65, -79:07:43.5 with an error of 0".5. At a mean time of 01:40:20 
UT, we measure the following preliminary AB magnitudes:

g' > 21.6,
r' = 20.6 +/- 0.2,
i' = 19.5 +/- 0.1,
z' = 19.2 +/- 0.1,
J  = 19.0 +/- 0.2,
H  = 18.5 +/- 0.2, and
K  > 17.6.

We also detect clear fading in the J band. We propose this source to be 
the afterglow of GRB 140614A.

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