TITLE:   GCN CIRCULAR
NUMBER:  17003
SUBJECT: GRB 141004A: Continued Late Time RATIR Optical and NIR Observations
DATE:    14/10/31 18:59:43 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), Jos�� A. de Diego (UNAM), Leonid
Georgiev (UNAM), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (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
Astron��mico Nacional on Sierra San Pedro M��rtir from 2014/10 31.31 to
2014/10 31.46 UTC (26.34 to 26.48 days after the BAT trigger), obtaining
a total of 2.84 hours exposure in the r, i and z bands.

We continue to detect the source reported from previous epochs of RATIR
observations (Littlejohns, et al., GCN 16963; GCN 16937; GCN 16887). We
obtain the following detections and upper limit (3 sigma):

  r     23.62 +/- 0.19
  i     23.17 +/- 0.15
  z     > 21.09

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. In comparison to our previous
epochs of observations, the source appears to have brightened in the r
and i bands, consistent with an emerging supernova similar to SN 1998bw
(Schulze, et al., GCN 16936).

We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.