[vsnet-grb-info 18753] GRB 161117A: SMARTS optical/IR afterglow observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20202
SUBJECT: GRB 161117A: SMARTS optical/IR afterglow observations
DATE:    16/11/22 01:11:47 GMT
FROM:    Bethany Cobb at GWU  <bcobb at gwu.edu>

B. E. Cobb (GWU), reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 161117A
(GCN 20179, Cummings et al.) at two epochs (with mid-exposure times of
2016-11-17 02:38 UT & 2016-11-18 01:47 UT). For each epoch, several
dithered images were obtained with total summed exposure times of
15 min in V and I and 12 min in J and K.

The fading afterglow of GRB 161117A (e.g. GCN 20179, Cummings et al.;
GCN 20180, Malesani et al.; GCN 20181, D'Avanzo et al.) was detected
with the following preliminary magnitudes (or 3-sigma limits):

mid-exposure
time post-burst
(hours)            V mag            I mag             J mag             K
mag
1.03333          19.42+/-0.10  18.69+/-0.07  18.40+/-0.15  16.49+/-0.11

24.19361        >22.3              >21.1             >18.5             >16.7

(Optical photometry is calibrated against Landolt standard stars
and IR photometry is calibrated against 2MASS stars in the field.)