[vsnet-grb-info 5303] GRB 071025: R/I-band update

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6994
SUBJECT: GRB 071025: R/I-band update
DATE:    07/10/25 07:56:36 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim at astro.snu.ac.kr>

  M. Im, I. Lee (Seoul National University), and Y. Urata
  (Saitama University) on behalf of the EAFON team:

   We coninue examination of  the data obtained with
  the Mt. Lemmon (Arizona, US) 1.0m telescope. The afterglow appears
  to be decaying rapidly after ~2400 secs of the burst.
   Re-examination of R-band images show a faint smudge which could
  be due to the afterglow. The detection is consistent with GCN
  report 071025 (Rykoff et al.), and we set the limit of R -I > ~1.7 mag
  from our R-band observation. Note that our R-band filter has a
  long tail toward red wavelenth.
   Below are rough estimates of I-band magnitudes based on USNO-B stars
  (error ~ 0.15mag).


    Star time (UT)    Exp Time      I mag
--------------------------------------
     04:38:08           300s      16.8
     05:08:42           300s      17.2
     05:30:48           300s      18.1

   Further examination of the BVRI data is ongoing to check
  whether this is a red GRB or high-z GRB.

   This message may be cited.

   We acknowldege the help of the LOAO operators, J.H. Yoon,
  for this observation.