[vsnet-grb-info 14157] GRB 131108A: NOT optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15471
SUBJECT: GRB 131108A: NOT optical observations
DATE:    13/11/09 06:11:42 GMT
FROM:    Dong Xu at DARK/NBI  <dong.dark at gmail.com>

D. Xu, D. Malesani (DARK/NBI), T. Pursimo (NOT) report on behalf of a
larger collaboration:

We observed the Swift/XRT field of Fermi-detected GRB 131108A (Racusin
et al., GCN 15464; Stroh & Kennea, GCN 15468) using the 2.5m Nordic
Optical Telescope (NOT) equipped with the MOSCA camera. We obtained
SDSS ugriz frames, starting at 04:46:48 UT on 2013-11-09 (i.e., 8.081
hr after the Fermi/LAT trigger).

The optical afterglow is detected at the border of the XRT error
circle reported in Stroh & Kennea (GCN 15468) at coordinates

R.A. (J2000)  = 10:26:00.48
Dec. (J2000) = +09:39:44.05

Error Radius: ~0.5 arcsec

thus being consistent with the XRT position, as reported in Gorosabel
et al. (GCN 15469). In particular, the ugriz SED shows a clear drop at
the wavelength range corresponding to the spectroscopic redshift of
z=2.40 in de Ugarte Postigo et al. (GCN 15470).