[vsnet-grb-info 15677] GRB 141026A: Continued RATIR Optical and NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16965
SUBJECT: GRB 141026A: Continued RATIR Optical and NIR Observations
DATE:    14/10/27 16:56:57 GMT
FROM:    Nat Butler at Az State U  <natbutler at asu.edu>

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), 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), and
Harvey Moseley (GSFC) report:

We observed the field of GRB 141026A (Hagen, et al., GCN 16950)) 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 27.13 to 2014/10 27.53 UTC (24.48 to
34.08 hours after the BAT trigger), obtaining a total of 4.64 hours
exposure in the r, i, and z bands.

The optical afterlow (Littlejohns et al., GCN 16952; also Perley et al.,
GCN 16955, Varela et al., GCN 16953, Gorosabel et al., GCN 16954, Butler,
et al., GCN 16962) continues to fade.  In comparison with 2MASS, we obtain
the following detections and upper limit (3-sigma):

  r     22.94 +/- 0.16
  i     23.16 +/- 0.22
  z  >  20.1

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.  The source appears to have faded
roughly as t^(-0.5) since our last epoch (GCN 16962).

We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.  Further observations are planned.