TITLE:   GCN CIRCULAR
NUMBER:  14432
SUBJECT: GRB 130420B: RATIR Optical and NIR Observations
DATE:    13/04/21 17:24:52 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),
Jos� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes�s Gonz�lez (UNAM),
Carlos Rom�n-Z��iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC)
report:

We observed the field of GRB 130420B (Oates et al., GCN 14411) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron�mico Nacional on
Sierra San Pedro M�rtir from 2013/04 21.15 to 2013/04 21.29 UTC (14.54 to
18.10 hours after the BAT trigger), obtaining a total of 1.32 hours
exposure in the r' and i' bands and 0.55 hours exposure in the Z, Y, J, and
H bands.

For a source within the Swift-XRT error circle (Page et al., GCN 14430), in
comparison with SDSS DR8 and 2MASS, we obtain the following upper limits
(3-sigma) in the AB magnitude system:

 r'> 23.19
 i'> 22.99
 Z > 21.87
 Y > 21.39
 J > 21.20
 H > 20.53

These magnitudes are not corrected for Galactic extinction in the direction
of the GRB.

We thank the staff of the Observatorio Astron�mico Nacional in San Pedro
M�rtir.