[vsnet-grb-info 12547] GRB 121027A: nIR afterglow candidate with AAT

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13911
SUBJECT: GRB 121027A: nIR afterglow candidate with AAT
DATE:    12/10/27 20:11:13 GMT
FROM:    Rhaana Starling at U of Leicester  <rlcs1 at star.le.ac.uk>

R.L.C. Starling (U. Leicester), A.J. Levan (U. Warwick), K. Wiersema (U. Leicester), A. Lopez Garcia (AAO/Macquarie University), N.R. Tanvir (U. Leicester), T. Young (ANU), L. Spitler (Macquarie University/AAO) and S. Lee (AAO) report:

We triggered near-infrared observations with IRIS2 on the Anglo-Australian Telescope for GRB 121027A, beginning ~3.5 hours after the Swift BAT trigger (Evans et al. GCN Circ. 13907).

The field was observed for 2x10 minutes in each of J, H and K bands. In a preliminary analysis of the K band data (beginning 13:49 UT) we clearly detect a source within the enhanced XRT error circle (www.swift.ac.uk/sper/536831) at position:

RA   04 14 23.44
Dec -58 49 47.4 (J2000)

with approximate magnitude K(AB)=21.10 +/- 0.13.

The source is not discernable from the J and H band images. These, however, do not go as deep owing to variable weather conditions; the limiting magnitude in H(AB) is 21.3 (3-sigma, beginning 13:22 UT).  


These data were obtained under programme AAT/12B/30.