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GCN Circular 13920

GRB 121027A: Brightening IR counterpart
2012-10-29T08:36:06Z (12 years ago)
Andrew Levan at U.of Leicester <>
A.J. Levan (U. Warwick), R.Starling, N.R. Tanvir, K. Wiersema (U.
Leicester), A. R. Lopez-Sanchez (AAO/Macquarie University), T. Young
(ANU), K. Glazebrook (Swinburne), L. Spitler (Macquarie University/AAO),
and S. Lee (AAO) report:

"We observed the candidate afterglow of GRB 121027A (Evans et al.
GCN 13906; Starling et al. GCN 13916) with the Anglo Australian
Telescope for a second epoch on the night of 28 October 2012. The
second epoch was obtained ~32 hours after the burst, and 26 hours
after the first epoch reported in Starling et al. (GCN 13916). We
clearly detect the afterglow candidate, and find that it has
brightened by approximately 1 magnitude in the K-band between the
two epochs. This confirms it as the infrared afterglow of GRB
121027A. We note that rising behaviour in the IR over this time
period is extremely unusual, and given the extremely bright, and
long lived X-ray afterglow (e.g. Serino et al. GCN 13908) could be
indicative of an event similar in nature to Swift J1644+57."
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