[vsnet-grb-info 15374] GRB 140730A: GROND Upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16664
SUBJECT: GRB 140730A: GROND Upper limits
DATE:    14/08/02 23:55:14 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann at tls-tautenburg.de>

D. A. Kann (TLS Tautenburg), C. Delvaux and Jochen Greiner (both MPE
Garching) report on behalf of the GROND team:

We observed the field of GRB 140730A (Swift trigger 607742; Markwardt et
al., GCN #16642) 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 08:36 UT on 2014-08-02, 2.52 days after the GRB
trigger. They were performed at an average seeing of 1".2 and at an
average airmass of 1.4.

Based on images with exposure times of 2250 s in g'r'i'z' and 1200 s in
JHK, we do not detect a source within the Swift-XRT error circle reported
by Goad et al. (GCN #16644) down to to the following 3-sigma AB
magnitudes:

g' > 25.3 mag,
r' > 25.4 mag,
i' > 24.7 mag,
z' > 24.4 mag,
J > 21.0 mag,
H > 20.3 mag, and
K > 18.0 mag.

The given limits are derived based on calibrating the images against the
GROND zeropoints and 2MASS field stars and are not corrected for the
Galactic foreground extinction corresponding to a reddening of E_(B-V)=
0.09 in the direction of the burst (Schlegel et al. 1998).