TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2739
SUBJECT: GRB 040924, optical follow-up
DATE:    04/09/24 21:47:19 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

D. Pérez-Ramírez (Univ. de Jaén), P. Tristram (Univ. of Canterbury),
J. Gorosabel, M. Jelínek (IAA-CSIC, Granada), Ch. Okada (Nagoya
Univ.), Ph. Yock (Univ. of Auckland), A. de Ugarte Postigo, S. Guziy
and A. J. Castro-Tirado (IAA-CSIC)

report:

Following the detection by HETE-2 of the short/soft GRB 040924
(Fenimore et al. GCN Circ. 2735) we imaged the error box with
the 0.6 m telescope at Mt. John Observatory (+ MOA camera)
in the wide R-band filter. A 300-s single image was obtained
through clouds starting on Sep 24, 13:53 UT (2.0 hr after the
event). Additional images (3 x 300-s) were obtained at high airmass
under clear sky conditions, about 5 hr after the GRB onset. At the
position of the optical counterpart proposed by Fox and Moon
(GCN Circ. 2734) we do not see any optical source down to about
R = 19 and R = 20.5 at these two epochs. If this is the true optical
counterpart, the fast decay would resemble the one of the proposed
counterpart for the short/hard GRB 000313 as detected by BOOTES
(Castro-Tirado et al. 2002, A&A 393, L55). A more in-depth analysis
of the images is in progress.

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