GCN Circular 13664
Subject
GRB 120817A: FTN and FTS observations
Date
2012-08-17T11:02:47Z (12 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), C.G. Mundell, C.J. Mottram,
F. Virgili (LJMU), A. Gomboc (U. Ljubljana) report on
behalf of a larger collaboration:
The 2-m Faulkes Telescope North (FTN) automatically began observing
GRB 120817A (Gompertz et al. GCN Circ. 13661) on August 17 2012,
06:53:57 UT corresponding to 4.2 minutes post burst trigger
with BVRi' filters. Within the XRT error circle (Perri et al.
GCN Circ. 13662), close to a USNOB1 object we detect a faint,
uncatalogued, possibly fading source at the following position
R.A. = 16:42:45.92
Dec = -38:21:12.4 (J2000)
with an uncertainty of about 1".
The detection is marginal, with an estimated magnitude of
19.3 +/- 0.4 in the R band at a mean time of 17.4 minutes
(60 s exposure) calibrated against nearby USNOB-1 stars.
The 2-m Faulkes Telescope South (FTS) began observing at 77 min
post burst. In a stacked R-band frame we find marginal evidence
for fading, with R=19.8 +- 0.3 mag at a mean time of 105 min
(total exposure of 360 s). The nearby USNOB1 object is compatible
with being constant between the two observations.
The comparison between the FTN and FTS R-band images is available at
http://www.fe.infn.it/u/guidorzi/GRB120817A_XRT_FT_candidate.jpg
