TITLE:   GCN CIRCULAR
NUMBER:  19779
SUBJECT: GRB 160804A: RATIR Optical and NIR Observations 
DATE:    16/08/05 17:40:09 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@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), 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 observed the field of GRB 160804A (Marshall et al., GCN Circular
19761) 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 2016/08 5.16 to
2016/08 5.27 UTC (26.33 to 29.04 hours after the BAT trigger), obtaining
a total of 1.78 hours exposure in the r and i bands and 0.75 hours
exposure in the Z, Y, J, and H bands.

We detect a source coincident with Swift/UVOT source (Breeveld et al.,
GCN Circular 19764) with the following magnitudes and 3-sigma upper
limit:

  r = 21.29 +/- 0.02
  i = 20.90 +/- 0.02
  Z = 21.12 +/- 0.19 
  Y = 21.04 +/- 0.29 
  J = 20.52 +/- 0.23 
  H > 20.51

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.