[vsnet-grb-info 7694] GRB090424: BVRI/R-band detection after 15 hrs burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9248
SUBJECT: GRB090424: BVRI/R-band detection after 15 hrs burst
DATE:    09/04/25 06:52:02 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim at astro.snu.ac.kr>

  M. Im, W. Park, Y. Jeon, I. Lee (CEOU/Seoul National Univ),
  Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team.

   We took BVRI-band images of GRB090424 (GCN 9223)
  using the 1.0m telescope at Mt. Lemmon (Arizona, US)
  operated by the Korea Astronomy Space Science Institute.
   The whole sequence of the observation started at
  2009 April 25, 04:30:19 UT, among which R-band observation
  started at 04:58:32.22.

   From a stacked image of 6 frames (3 min exp. each),
  we cleary detect the afterglow at R=19.9 +- 0.14 mag, calibrated
  against USNO-B1 stars in the vicinity. The mid-point of the
  obseravation is April 25, 05:10:57 UT (14.97 hrs after
  the burst).
   Analysis of the BVI data is ongoing.

   We thank the LOAO operator, J. Yoon for his assistance for this
  observation.