GCN Circular 14830
Subject
GRB 130609A: P60 nondetection
Event
Date
2013-06-09T05:28:54Z (13 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) and S. B. Cenko (GSFC) report:
The Palomar 60-inch telescope automatically responded to GRB 130609A
(Cummings et al., GCN 14828) and began taking observations at 04:03:23
UT (58.25 minutes after the BAT trigger) as soon as the sky became dark.
A sequence of cycled 60-second r, i, and z images was acquired. We
detect no source consistent with the XRT localization in either
individual images or in combined stacks of the first 6 images in each
filter. Approximate 5-sigma limiting magnitudes from the combined
images at an approximate mean time of 4:20 UT (75 minutes after the GRB
trigger) are:
r > 22.5
i > 21.5
z > 20.9
These limits are suggestive of a dark GRB. Cummings et al. report a
detection of significant excess absorption in the XRT spectrum, which
may indicate a dust-extinguished (as opposed to high-redshift) event,
although given the quoted errors there the excess may be only marginal.
NIR follow-up is highly encouraged.