GCN Circular 16341

GRB 140408A: Withdrawal of afterglow candidate

F. Knust, K. Varela, C. Delvaux (all MPE Garching), D.A. Kann (TLS
Tautenburg) and J. Greiner (MPE Garching)  report on behalf of the GROND
team: 

We observed the GRB 140408A field again on further three epochs,
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).


The afterglow candidate reported in Varela et al. (GCN #16089) remained
constant, thus this source is a fore- or background source and not the
afterglow of GRB 140408A.

For the first epoch as reported in Varela et al. (GCN #16089), no other
source is seen in the 1".8 Swift-XRT refined error circle
(http://www.swift.ac.uk/xrt_positions/00595141/) down to limiting magnitudes
(all in the AB system) of

g' > 25.8 mag, 
r' > 25.6 mag, 
i' > 25.0 mag, 
z' > 25.0 mag, 
J > 22.1 mag, 
H > 21.5 mag, and 
K > 20.0 mag.

The given limits are based on calibrating the images against GROND
zeropoints and 2MASS field stars, and are not corrected for the Galactic
foreground extinction corresponding to a reddening of E_(B-V)= 0.16 in the
direction of the burst (Schlegel et al. 1998).