[vsnet-grb-info 13990] GRB 131004A: optical afterglow from the NOT

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15304
SUBJECT: GRB 131004A: optical afterglow from the NOT
DATE:    13/10/04 22:44:30 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at dark-cosmology.dk>

D. Xu, D. Malesani, J. Hjorth (DARK/NBI), P. Jakobsson (Univ. Iceland), 
T. Kruehler (ESO Santiago), Nicolaas Groeneboom, and Anders Hafreager 
(Univ. Oslo), report:

We observed the field of GRB 131004A (Hagen et al., GCN 15303) using the 
NOT equipped with AlFOSC. Consistent with the XRT position, we detect a 
new source at coordinates:

RA = 19:44:27.08
Dec = -02:57:30.2

The source is not visible in the DSS, and brighter than its limiting 
magnitude, hence it is very likely the afterglow of GRB 131004A. At a 
time of 0.43 hr after the GRB, we measure R = 20.2 +- 0.1 mag compared 
to nearby USNO-B1 R2 magnitudes, where the error is mostly due to 
calibration.