[vsnet-grb-info 12390] GRB 120913B: TAROT La Silla observatory optical detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13765
SUBJECT: GRB 120913B: TAROT La Silla observatory optical detection
DATE:    12/09/14 00:41:33 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz at free.fr>

Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:

We imaged the field of GRB 120913B detected by SWIFT
(trigger 533613) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 30.6s after the GRB trigger
(17.7s after the notice). The elevation of the field decreased
from 26 degrees above horizon and weather conditions
were good.

We detect a new fading source in the error box given
by SWIFT. We detected the candidate couterpart
mentioned by LaCluyze et al. (GCNC 13764)
at the following position (+/- 2 arcsec):

RA(J2000.0) = 14h 14m 38.57s
DEC(J2000.0) -14d 30' 55.8"

OT raised until R=15.8 5 min after the GRB.
Now the afterglow is fading.

Magnitudes were estimated with the nearby NOMAD1 star
0754-0289300 (R.A.=213.6332611 Decl=-14.5238889 J2000)
R=15.99. MAgnitutes are not corrected for galactic dust
extinction.

N.B. Galactic coordinates are lon=331.3041 lat=+43.7095
and the galactic extinction in R band is about 0.2 magnitude
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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