TITLE:   GCN CIRCULAR
NUMBER:  15258
SUBJECT: GRB 130925A: RATIR Optical and NIR Observations
DATE:    13/09/26 01:55:31 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 (UCSC),
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 130925A (Lien, et al., GCN 15246) 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 2013/09 25.27 to 2013/09 25.50 UTC (2.30 to
7.81 hours after the BAT trigger), obtaining a total of 3.67 hours exposure
in the r and i bands and 1.43 hours exposure in the Z, Y, J, and H bands.

We find an uncatalogued source in the enhanced Swift-XRT error circle
(Evans et al., GCN 15251).  In comparison with USNO-B1 and 2MASS, we obtain
the following detections and upper limits (3-sigma):

  r     22.26 +/- 0.11
  i     21.75 +/- 0.10
  Z     20.25 +/- 0.06
  Y     20.77 +/- 0.14
  J     19.98 +/- 0.07
  H     19.85 +/- 0.12

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.  The source is spatially coincident
and about as bright as the source reported by Sudilovsky et al. (GCN
15247), which was observed minutes rather than hours after the GRB.
 Further observations are planned.

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