GCN Circular 10091
Subject
GRB 091026: GROND Upper Limits
Event
Date
2009-10-27T05:38:20Z (17 years ago)
From
Adria C. Updike at Clemson U <aupdike@clemson.edu>
Robert Filgas (Tautenburg Obs.), Adria Updike (Clemson University), Arne
Rau, and Jochen Greiner (both MPE Garching) report on behalf of the GROND
team:
We observed the field of GRB 091026 (Swift trigger 373871; Markwardt et
al., GCN #10081) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla
Observatory (Chile).
Observations started at 00:48 UT on Oct 27, 2009, 11.6 hours after the GRB
trigger. They were performed at an average seeing of 2" and at an average
airmass of 1.94.
We do not detect a source within the Swift-XRT error circle reported by
Evans et al. (GCN #10084) down to
g' > 24.8 mag,
r' > 24.2 mag,
i' > 23.9 mag,
z' > 23.7 mag,
J > 22.2 mag,
H > 21.3 mag and
K > 20.2 mag.
Magnitudes are given in the AB system and calibrated against USNO as well
as 2MASS field stars, and are not corrected for the expected Galactic
foreground extinction corresponding to a reddening of E_(B-V) = 0.13 mag
in the direction of the burst (Schlegel et al. 1998).