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GCN Circular 36654

GRB 240529A : MITSuME Akeno optical afterglow detection
2024-06-10T11:17:09Z (3 days ago)
Masafumi Niwano at Tokyo Institute of Technology <>
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M. Niwano, I. Takahashi, M. Sasada, N. Higuchi, S. Hayatsu, H. Seki, S. Joshima, Y. Kubo, H. Hagio, Y. Yatsu and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:

We observed the field of GRB 240529A (Eyles-Ferris et al. GCN 36556) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno.

The observation with a series of 60 sec exposures started at 2024-05-29 15:11:22 UT (12.2 hrs after the Swift trigger). We stacked the images in good conditions. Then we detected point source in the Ic-band image at the Swift/UVOT position (Eyles-Ferris et al. GCN 36556). Here we report the Ic-band photometry on the image subtracted with a reference image taken at 2024-06-04 (5 days after the trigger), and the 5-sigma upper-limits as follows.

T0+[hrs] | MID-UT | T-EXP[sec] | magnitudes of aperture photometry
12.3 | 2024-05-29 16:10:25 | 1080 | g’>18.1, Rc>17.9, Ic=17.5+/-0.2
T0+ : Elapsed time after the trigger
T-EXP: Total Exposure time

We used the PS1 catalog for flux calibration. The catalog magnitudes in PS1 g, r and i bands were converted to our g'-, Rc- and Ic-band magnitudes following Tonry et al. (2012), Table 6. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ;
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