TITLE:   GCN CIRCULAR
NUMBER:  22192
SUBJECT: GRB 171205A: SMARTS optical/IR afterglow observations
DATE:    17/12/06 20:08:38 GMT
FROM:    Bethany Cobb at GWU  <bcobb@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 171205A
(GCN 22177, D'Elia et al.) with a mid-exposure time of about
24.5 hrs post-burst (2017-12-06 07:50 UT). Total summed exposure
times amounted to 15 min in V and I and 12 min in J and K.

The afterglow of GRB 171205A (e.g. GCN 22179, Osborne et al.;
GCN 22180, Izzo et al.; GCN 22181, Emery et al.) was detected
with the following preliminary magnitudes:

V mag = 18.5 +/- 0.1
I mag = 17.7 +/- 0.1
J mag = 17.6 +/- 0.1
K mag = 16.2 +/- 0.1

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