[vsnet-grb-info 15598] GRB 141004A: RATIR Optical Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16887
SUBJECT: GRB 141004A: RATIR Optical Observations
DATE:    14/10/05 09:34:12 GMT
FROM:    Owen Littlejohns at Az State U  <olittlej at 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 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 5.30 to 2014/10 5.35
UTC (7.82 to 9.15 hours after the BAT trigger), obtaining a total of
1.07 hours exposure in the r and i bands.

We detect the source reported by Swift/UVOT (D'Elia, et al., GCN 16878)
and the 3.6m TNG telescope (D'Elia, et al., GCN 16881). We obtain the
following detections:

  r     22.35 +/- 0.13
  i     22.11 +/- 0.12

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. In comparison to the earlier TNG
observations we note that the GRB has faded with an approximate
temporal power-law index of t^(-1.0).

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