[vsnet-grb-info 12721] GRB 121211A: Continued RATIR Optical and NIR Observations, Fading

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14080
SUBJECT: GRB 121211A: Continued RATIR Optical and NIR Observations, Fading
DATE:    12/12/13 22:56:58 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 (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 121211A (Mangano, et al., GCN 14057) 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 for a second time from 2012 Dec 13.46 to 2012 Dec
13.57 UTC (45.2 to 47.8 hours after the BAT trigger), obtaining a total of
1.8 hours exposures in the r' and i' bands, 1.2 hours exposure in the Z and
J bands, and 10 minutes exposure in the Y and H bands.

For a source spatially coincident with the UVOT position (Chester et al.,
GCN 14063), in comparison with SDSS DR8 and 2MASS, we derive the following
detections and upper limits (3-sigma) in the AB magnitude system:

 r' 23.8 +/- 0.3  (delta= -0.9 +/- 0.4)
 i' 24.0 +/- 0.4  (delta= -0.8 +/- 0.4)
 Z  >22.4
 Y  >21.8
 J  >21.3
 H  >20.6

The delta values give the fade in 24 hours relative to the values quoted in
GCN 14077.  These magnitudes are not corrected for Galactic extinction in
the direction of the GRB.

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