GCN Circular 7581
Subject
GRB 080408: GROND detection of optical/NIR afterglow candidate
Date
2008-04-10T06:55:11Z (17 years ago)
From
Thomas Kruehler at MPE/MPI <kruehler@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).