[vsnet-grb-info 9077] GRB 100316A: R-band limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10565
SUBJECT: GRB 100316A: R-band limit
DATE:    10/04/02 12:51:11 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim at astro.snu.ac.kr>

Jang, M., Im, M. (SNU), and Y. Urata (NCU) report on behalf of
the EAFON collaboration:

  We observed GRB100316A in R-band starting at 2010 March16, 08:09:17UT,
or 20.78 ks after the BAT triggered (Baumgartner et al, GCN 10484),
using the 1.0m telescope at Mt.Lemmon in Arizona, U.S. operated
by Korea Astronomy Space Science Institute.

  No afterglow candidate was detected from a stacked image of eight 300s-frames.
within the error circle of the enhanced XRT position (Evans et al.,GCN 10490).
We estimate the 3-sigma limiting magnitude of the afterglow to be 
R ~ 22.0 +/- 0.2 at the midpoint time of the stacked image (~T0+21.98 ks)
by calibrating it against sixteen USNO-B1 stars near the GRB, using their
R2 magnitudes without correcting for the Galactic extinction.

  Our limit indicates fading of the optical afterglow candidate reported by
Gorosabel et al. (GCN 10488) shortly after.

  We thank the LOAO operator, I. Baek for her help with the observation