[vsnet-grb-info 17506] GRB 160121A: RATIR Optical Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18935
SUBJECT: GRB 160121A: RATIR Optical Observations
DATE:    16/01/25 18:37:38 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan at astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), 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), Jos� A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jes�s Gonz�lez (UNAM), Carlos Rom�n-Z��iga (UNAM), Neil Gehrels (GSFC),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and
Vicki Toy (UMD) report:

We observed the field of GRB 160121A (Hagen et al., GCN Circular 18912)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
Astron�mico Nacional on Sierra San Pedro M�rtir from 2016/01 24.13 to
2016/01 24.42 UTC (61.29 to 68.12 hours after the BAT trigger),
obtaining a total of 4.27 hours exposure in the r, i and z bands.

We no longer detect the source previously reported by Watson et al.
(GCN Circular 18924). In comparison with the USNO-B1 and 2MASS catalogs,
we obtain the following 3-sigma upper limits:

   r > 22.97
   i > 22.94
   z > 20.10

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 Astron�mico Nacional in San Pedro
M�rtir.