[vsnet-grb-info 14148] GRB 131030A: Continued RATIR Optical and NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15462
SUBJECT: GRB 131030A: Continued RATIR Optical and NIR Observations
DATE:    13/11/06 19:36:04 GMT
FROM:    Owen Littlejohns at Az State U  <olittlej at 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 (ORAU/GSFC),
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 again observed the field of GRB 131030A (Troja, et al., GCN Circ.
15402) 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
2013/11 5.08 to 2013/11 5.34 UTC (124.95 to 131.33 hours after the
BAT trigger), obtaining a total of 4.24 hours exposure in the r and
i bands and 0.92 hours exposure in the Z, Y, J, and H bands.

We continue to detect the previously reported source in the r and i
bands (Littlejohns, et al., GCN Circ. 15420; Troja, et al., GCN Circ.
15402). For a source within the Swift-XRT error circle, in comparison
with the SDSS DR9 and 2MASS, we obtain the following detections and
upper limits (3-sigma):

  r     23.17 +/- 0.14
  i     22.73 +/- 0.14
  Z     > 22.82
  Y     > 22.35
  J     > 20.05
  H     > 19.38

A further epoch of observations was also conducted from 2013/11 6.09
to 2013/11 6.34 UTC (149.15 to 155.17 hours after the BAT trigger),
obtaining a total of 3.73 hours exposure in the r and i bands and 1.53
hours exposure in the Z, Y, J, and H bands. The source was detected in
the r and i bands once more. For a source within the Swift-XRT error
circle, in comparison with the SDSS DR9 and 2MASS, we obtain the
following detections and upper limits (3-sigma):

  r     23.41 +/- 0.18
  i     23.06 +/- 0.18
  Z     > 22.74
  Y     > 22.25
  J     > 21.97
  H     > 21.39

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. In comparison with previous
epochs of RATIR observations, the source continues to fade in both the
r and i band.

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