GCN Circular 16534
Subject
GRB140706A: GROND detection of the Optical/NIR afterglow
Event
Date
2014-07-07T10:05:11Z (12 years ago)
From
Patricia Schady at MPE/Swift <pschady@mpe.mpg.de>
P. Schady (MPE Garching), S. Klose (TLS Tautenburg) and J.Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 140706A (Swift-603587; Marshall et al., GCN #16531) 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 ESO La Silla Observatory (Chile).
Observations started at 09:01UT on 7th-July, 13.5 hours after the GRB trigger, and are continuing. They were performed at an average seeing of 1.3� and at an average airmass of 1.5.
We found a single point source within the 2.2" Swift-XRT enhanced error circle reported by Beardmore et al. (GCN #16532) consistent with the UVOT position (Marshall et al., GCN #16531).
Based on the first 8 min exposure, we estimate preliminary magnitudes (all in AB system) of
g' = 22.4 +/- 0.1 mag,
r' = 22.1 +/- 0.1 mag,
i' = 21.9 +/- 0.1 mag,
z' = 21.5 +/- 0.1 mag,
J > 20.9 mag,
H > 20.3 mag, and
K > 18.8 mag.
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)=0.02 mag in the direction of the burst (Schlegel et al. 1998).