[vsnet-grb-info 13507] GRB 130606A - Liverpool Telescope and Faulkes Telescope North optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14840
SUBJECT: GRB 130606A - Liverpool Telescope and Faulkes Telescope North optical observations
DATE:    13/06/09 21:43:42 GMT
FROM:    Francisco Virgili at Liverpool John Moores U  <fjv at astro.livjm.ac.uk>

F.J. Virgili, C.G. Mundell (LJMU), A. Melandri (INAF-OAB), and A. Gomboc 
(U. Ljubljana) report:

Observations of GRB 130606A (Ukwatta et al., GCN 14781) with the 2-m 
robotic Liverpool Telescope automatically performed between 48 and 80 
minutes after the GRB trigger confirms a detection of the afterglow in 
the r'-band with magnitude

r' = 21.9 ± 0.29 at 49.95 minutes

consistent with reported values at similar epochs (Xu et al. 14783) and 
dimmer than times around 100 minutes post trigger (Leonini et al., GCN 
14791; Masi et al., GCN 14789; Sonbas et al., GCN 14797), possibly 
indicating mild re-brightening.  This detection clarifies that the 
afterglow has not yet dropped out of the r'-band at the times coincident 
with our i' and z' band detections (Virgili et al., GCN 14785) and 
continues to be detected until at least 6.4 hrs after the initial 
trigger (Afonso et al., GCN 14807).

In addition, the 2-m Faulkes Telescope North and Liverpool Telescope 
performed late-time follow up observations, resulting in a 3-sigma 
upper-limit of

r' > 23.4 at 849.73 min (14.16 hr post-trigger; FTN)
r' > 24 at 1683.67 minutes (= 28.06 hr; LT)

and an additional i'-band detection of

i' = 23.76 ± 0.22 @ 28.60 hr (= 1716.51 minutes; LT),

in a co-added series of 6x300s exposures, which are consistent with 
values reported by Trotter et al. (GCN 14815) and Butler et al. (GCN 
14824).  FTN images have been acquired with the R-Bessell filter and 
calibrated against nearby SDSS catalogue stars.