[vsnet-grb-info 15143] GRB 140422A: GROND Upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16435
SUBJECT: GRB 140422A: GROND Upper limits
DATE:    14/06/22 18:07:36 GMT
FROM:    Corentin Delvaux at MPE  <delvaux at mpe.mpg.de>

M. Tanga, C. Delvaux and J. Greiner (all MPE Garching) report on behalf of
the GROND team:

We observed the field of GRB 140622A (Swift trigger 602278; D'Elia et al.,
GCN #16433) 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 09:40 UT on June 22, 2014, 0.07 hours after the
GRB trigger. They were performed at an average seeing of 1.3 and at an
average airmass of 1.23.

We do not detect a source within the Swift-XRT error circle reported by
D'Elia et al. (GCN  #16433) down to the following 3-sigma AB magnitudes:

g' > 24.3 mag,
r' > 24.3 mag,
i' > 24.1 mag,
z' > 24.1 mag,
J > 21.3 mag,
H > 20.9 mag, and
K > 19.4 mag.

We report the detection of a faint object at the border of the 2.6"
Swift-XRT error circle at coordinates

   RA(J2000)  =  21:08:41.73
   Dec(J2000) = -14:25:06.5

This object is detected in g', r', i', z' and J and there is no evidence
of fading. Its estimated AB magnitudes are

g' = 23.4 +/- 0.2 mag,
r' = 23.4 +/- 0.2 mag,
i' = 22.5 +/- 0.1 mag,
z' = 22.2 +/- 0.1 mag, and
J = 20.9 +/- 0.3 mag.

At this time, we cannot assert that this object is the host galaxy of GRB
140622A.

The given limits and magnitudes are derived 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)= 0.07 mag in the direction of the burst (Schlegel et
al. 1998).