[vsnet-grb-info 14323] GRB 131229A: Magellan upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15637
SUBJECT: GRB 131229A: Magellan upper limit
DATE:    13/12/30 07:01:04 GMT
FROM:    Ryan Chornock at Harvard  <rchornock at cfa.harvard.edu>

R. Chornock, W. Fong, and E. Berger (Harvard) report:

We observed the field of GRB 131229A (Page et al., GCN 15627) using LDSS3 on the 
6.5 m Magellan Clay telescope starting 21 minutes after the BAT trigger. Initial 
r' and i' images in 0.8" seeing revealed no clear counterpart, consistent with 
the upper limits reported by other groups (Perley, GCN 15628; Zheng et al., GCN 
15629; Perley et al., GCN 15630; Graham et al., GCN 15636; de Pasquale et al., 
GCN 15633). We then obtained a sequence of 7x180s z'-band images starting at 
t=+34 min after the trigger. The sources labeled A and B by Perley et al. (GCN 
15628) are visible outside of the enhanced XRT error circle (Evans et al., GCN 
15631). However, a stack of our images reveals no sources within the enhanced 
XRT error circle. We set a 3-sigma upper limit of z'>24.3 mag (AB) at a midpoint 
of t=+49 minutes.