GCN Circular 22383
Subject
GRB 180205A: GROND detection of the NIR/optical afterglow
Event
Date
2018-02-05T06:02:56Z (8 years ago)
From
Jan Bolmer at MPE/Garching <jan@bolmer.de>
J. Bolmer (ESO/MPE) and D.A. Kann (HETH/IAA-CSIC) report:
We observed the field of GRB 180205A (Swift trigger 808625; P.A. Evans et al.,
GCN 22381) 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 04:38 UT on February 05, 2018, 13 minutes after
the GRB trigger. They were performed at an average seeing of 1".1 and at
an average airmass of 1.33.
We clearly detect the NIR/optical transient of GRB 181205A reported
also by Zheng et al., GCN 22382.
Based on total exposures of 200 seconds in g���r'i'z��� and 180 seconds in JHK
at a midtime of 04:43 UT, 17 minutes after the burst, we measure
the following preliminary magnitudes (AB magnitude
system):
g' = 16.83 +/- 0.01 mag,
r' = 16.68 +/- 0.01 mag,
i' = 16.56 +/- 0.01 mag,
z' = 16.38 +/- 0.01 mag,
J = 16.22 +/- 0.02 mag,
H = 16.05 +/- 0.02 mag, and
K = 16.08 +/- 0.14 mag.
Magnitudes and are calibrated against PanSTARRS and 2MASS
field stars and are not corrected for the Galactic foreground extinction
corresponding to a reddening of E_(B-V)= 0.03 mag in the direction of the
burst (Schlegel et al. 1998).
Observations are continuing.
We thank Markus Rabus for the excellent support from La Silla.