TITLE:   GCN CIRCULAR
NUMBER:  15057
SUBJECT: GRB 130722A: RATIR Optical Observations
DATE:    13/07/29 05:13:38 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 (UCSC), 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 130722A (Melandri, et al., GCN 15013) 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 2013/07 23.23 to 2013/07 23.39 UTC (21.24 to
25.00 hours after the BAT trigger), obtaining a total of 2.33 hours
exposure in the i' band.

We detect the candidate GRB host galaxy from Melandri et al. (GCN 15015)
noting also that the source is extended. In comparison with USNO-B1, we
obtain:

 i'     19.58 +/- 0.02

This magnitude is in the AB system and not corrected for Galactic
extinction in the direction of the GRB.  We do not detect the candidate OT,
although it is likely blended with the host galaxy. In comparison with the
Faulkes measurement one night earlier, the OT has thus faded by at least
1.5 magnitudes.

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