TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2749
SUBJECT: GRB040924, RTT150 optical observation
DATE:    04/09/25 18:40:55 GMT
FROM:    Irek Khamitov at TUG  <irekk@tug.tug.tubitak.gov.tr>

I. Khamitov, Z. Aslan (TUG), C. Yesilyaprak (Akdeniz Univ.), U. Kiziloglu (METU),
E. Gogus, A. Alpar (Sabanci Univ.), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Bikmaev, N. Sakhibullin (KSU)

report:

   We observed the error box of GRB 040924 (Fenimore et al., GCN 2735) with
Russian-Turkish 1.5-m telescope (Bakyrlytepe, TUBITAK National Observatory,
Turkey). During continuous observations of the afterdlow candidate from
Sep. 24, 20:50UT to Sep. 25, 02:40UT (8.96--14.94 hours after the burst) 
weobtained 64x300s images in R. The observations were made under moderate
atmospheric conditions.

   We found that the afterglow candidate (Fox and Moon, GCN 2734) faided by
approximately 0.6 mag, from m_R=22.1 to 22.7, during our observations, 
which corresponds to power law decay with index -1.16.

   The absolute calibration was done according our mean photometric
solutions. For comparison one can use star at 02:06:23.3 +16:07:13 wich 
has m_R=19.8 according to our solutions. Brighter magnitide, reported by 
Fynbo et al. (GCN 2747) most likely is due to the difference in absolute
calibration.

Our light curve can be found at:

http://hea.iki.rssi.ru/~rodion/040924/lc_0924.jpg

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