[vsnet-grb-info 18516] GRB 160927A: Magellan imaging

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19964
SUBJECT: GRB 160927A: Magellan imaging
DATE:    16/09/28 18:36:06 GMT
FROM:    Wen-fai Fong at U of Arizona  <wfong at email.arizona.edu>

W. Fong (Univ. of Arizona), S. Sheppard (Carnegie DTM) and E. Berger
(Harvard) report:

We imaged the location of the short-duration GRB 160927A (Gibson et al.,
GCN 19952) with the Inamori-Magellan Areal Camera and Spectrograph (IMACS)
mounted on the Magellan/Baade 6.5-m telescope at a mid-time of 2016 Sep
28.00 UT (5.94 hr post-burst). We obtained 4x200-sec of r-band exposures in
0.75" seeing at an airmass of 1.9. We clearly detect the optical afterglow
(Tkachenko et al., GCN 19954; D'Avanzo et al., GCN 19956; Wiseman et al.,
GCN 19959; Xu et al., GCN 19960). Tied to 10 SDSS stars in the field, we
calculate a magnitude of r_AB=23.84 +/- 0.21, not corrected for Galactic
extinction in the direction of the burst.