TITLE:   GCN CIRCULAR
NUMBER:  16963
SUBJECT: GRB 141004A: Continued RATIR Late Time Optical and NIR Observations
DATE:    14/10/26 19:23:33 GMT
FROM:    Owen Littlejohns at Az State U  <olittlej@asu.edu>

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

We again observed the field of GRB 141004A (D'Elia, et al., GCN 16878)
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 2014/10 26.26 to
2014/10 26.52 UTC (21.27 to 21.55 days after the BAT trigger),
obtaining a total of 4.98 hours exposure in the r, i and z bands.

We continue to detect the source reported in previous epochs of RATIR
observations (Littlejohns, et al., GCN 16937, Littlejohns, et al., GCN
16887), with the following detections and upper limit:

  r     23.94 +/- 0.20
  i     23.38 +/- 0.15
  z     > 20.97

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. These magnitudes are broadly
consistent with our previous epoch of observations (Littlejohns, et al.,
GCN 16937). Further observations are planned.

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