[vsnet-grb-info 14906] GRB 140430A: Further VATT Optical Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16201
SUBJECT: GRB 140430A: Further VATT Optical Observations
DATE:    14/05/02 07:41:32 GMT
FROM:    Peter Garnavich at U of Notre Dame  <pgarnavi at nd.edu>

M. Kennedy (University College Cork), P. Garnavich (Notre Dame)

We again observed the field around GRB 140430A with the 1.8m Vatican
Advanced Technology Telescope (VATT; GCN 16196). Observations with the
VATT4K CCD were centered around 3:22 UT on 2014 May 2 (1848 minutes after
the burst). We obtained 5x300s exposures with the R-band filter in good
seeing. We detect the previously reported afterglow in the combined images.

With the same USNO comparison star used by Malesani et al (GCN 16193)
and Kennedy et al. (GCN 16196) we estimate the afterglow brightness
as R=21.7 +/- 0.1 at 30.81 hours after the burst. This is fainter
than the extrapolation of the power-law decay rate estimated for the
first seven hours and we conclude that optical power-law decay index has
steepened to 1.0 over the past day.