[vsnet-grb-info 17642] GRB 160223A: RATIR Optical and NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19079
SUBJECT: GRB 160223A: RATIR Optical and NIR Observations
DATE:    16/02/25 17:46:00 GMT
FROM:    Nat Butler at Az State U  <natbutler at asu.edu>

Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC),
José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM),
Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC),
John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We first observed the field of GRB 160223A (Markwardt, et al., GCN 19057)
with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org)
on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico
Nacional on Sierra San Pedro Mártir from 2016/02 23.15 to 2016/02 23.49 UTC
(3.65 to 11.79 hours after the BAT trigger), obtaining a total of 5.04
hours exposure in the r and i bands and 2.26 hours exposure in the Z, Y, J,
and H bands.  We observed a second time from 2016/02 24.12 to 2016/02 24.49
UTC (26.78 to 35.78 hours after the BAT trigger), obtaining a total of 5.02
hours exposure in the r and i bands and 2.12 hours exposure in the Z, Y, J,
and H bands.

We detect the afterglow (Bolmer, et al., GCN 19058) cleanly in the first
epoch.  In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the
following magnitudes:

 r = 18.13 +/- 0.01
 i = 17.43 +/- 0.01
 Z = 17.37 +/- 0.01
 Y = 17.20 +/- 0.01
 J = 17.08 +/- 0.01
 H = 16.81 +/- 0.01

The source is clearly fading during the first epoch.  In the second epoch,
we do not detect the source.  We obtain the following (3-sigma) upper
limits:

 r > 22.38
 i > 22.05
 Z > 21.49
 Y > 21.44
 J > 21.35
 H > 21.26

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.