TITLE:   GCN CIRCULAR
NUMBER:  16575
SUBJECT: GRB 140709A: Continued RATIR Optical and NIR Observations
DATE:    14/07/10 23:21:48 GMT
FROM:    Nat Butler at Az State U  <natbutler@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 140709A (Hagen, et al., GCN 16546) 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 from 2014/07 9.17 to 2014/07 9.46 UTC (2.76 to
9.93 hours after the BAT trigger), obtaining a total of 4.98 hours exposure
in the r and i bands and 2.09 hours exposure in the Z, Y, J, and H bands
and again from 2014/07 10.17 to 2014/07 10.42 UTC (26.77 to 32.87 hours
after the BAT trigger), obtaining a total of 4.27 hours exposure in the r
and i bands and 1.79 hours exposure in the Z, Y, J, and H bands.

We detect the afterglow candidate reported by Castro-Tirado et al. (GCN
16554; also Masi, et al., GCN 16559; Castro-Tirado, et al., GCN 16564) in
both epochs, adding a deeper integration for our first epoch as compared to
our initial report (Butler, et al., GCN 16547).  Relative to 2MASS and
using the RATIR zero-points, we find:

     7/09                   7/10
  r  24.28 +/- 0.45   23.85 +/- 0.31
  i  23.05 +/- 0.16   23.28 +/- 0.20
  Z >22.92             >22.68
  Y >22.40             >22.33
  J >22.30             >22.27
  H >21.94             >21.85

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.  Upper limits are 3-sigma.  We
cannot reliably confirm fading in this source.  We note that another RATIR
source outside of the Swift XRT error region (see, GCN 16547) does not
appear to fade and is not likely to be the afterglow to GRB 140709A.

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