[vsnet-grb-info 5936] GRB 080408: GROND detection of optical/NIR afterglow candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7581
SUBJECT: GRB 080408: GROND detection of optical/NIR afterglow candidate
DATE:    08/04/10 06:55:11 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler at mpe.mpg.de>

T. Kruehler, J. Greiner, A. Kupcu Yoldas, C. Clemens, A. Yoldas (all MPE
Garching) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching)
report on behalf of the GROND team:

We observed the field of GRB 080408 detected by SuperAGILE (Soffitta et
al., GCN #7571) simultaneously in g'r'i'z'JHK with GROND mounted at the
2.2m ESO/MPI telescope at La Silla Observatory (Chile).

Observations started at 23:22:39 UT on April 8th, 2008, 5h 10min, and 
continued on April, 9th at 23:21:34 UT, 29h 9min after the burst. Due to
visibility constraints, only about 1 hr of observations were obtained at
each epoch.

In the first epoch we detect a single point source in the XRT error 
circle (Page et al. GCN #7576) at

RA (J2000.0) = 07:38:39.59
DEC (J2000.0) = +33:18:14.9

with an uncertainty of 0.5".

The object is detected in all of the seven bands, implying a redshift
smaller than 3.5.

Preliminary photometry yields magnitudes of g' = 23.12, r' = 22.03, i' =
21.62, z' = 21.26, J = 20.60, H = 19.90 and K = 19.06, with typical 
errors of +/- 0.10 in g'r'i'z' and +/- 0.15 in JHK. Magnitudes are
calibrated against USNO and 2MASS field stars.

In the second night, the object had faded to a r' band magnitude of 23.2
+/- 0.2.

We therefore suggest this to be the afterglow of GRB 080408.

The given magnitudes are not corrected for the Galactic foreground
reddening of E(B-V)=0.04 mag (Schlegel et al., 1998).