[vsnet-grb-info 14032] GRB 131014A: RATIR Optical/NIR Afterglow Confirmation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15346
SUBJECT: GRB 131014A: RATIR Optical/NIR Afterglow Confirmation
DATE:    13/10/16 22:34:10 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja at nasa.gov>

Eleonora Troja (GSFC), 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), 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 reobserved the field of GRB 131014A (Fitzpatrick, et al., GCN 15332;
Desiante, et al., GCN 15333) 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
2013/10 16.36 to 2013/10 16.52 UTC (51.38 to 55.33 hours after the
GBM trigger), obtaining a total of 2.11 hours exposure in the r and i bands
and 0.88 hours exposure in the Z, Y, J, and H bands.

We do not detect the source reported in Troja et al. (GCN 15340).
In comparison with SDSS DR9 and 2MASS, we obtain the following upper
limits (3-sigma):

   r   >23.8
   i   >23.4
   Z   >22.4
   Y   >21.7
   J   >21.4
   H   >20.9

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

We note that the source reported in Troja et al. (GCN 15340) lies within 
the
XRT localization reported in Kennea et al. (GCN 15335), but is ~4 arcsec
offset from the XRT enhanced position (Evans et al., 15339).
However, the source shows evidence of fading in our latest exposures
(>3 sigma level, i band; 2-sigma level, r and Y band), suggesting that
it is associated with GRB131014A.

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