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GCN Circular 30936

Swift trigger 1078701: MITSuME Akeno optical upper limits
2021-10-13T06:01:01Z (3 years ago)
Naohiro Ito at Tokyo Tech <>
N. Ito, R. Hosokawa, K. L. Murata, Y. Imai, Y. Takamatsu, M. Niwano, R.
Noto, S. Sato, M. Takaku, R. Yamaguchi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of Swift/BAT trigger 1078701 (Bernardini et al., GCN
#30929) 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 10
sec exposures started at 2021-10-10 10:43:22 (46 seconds after Swift
trigger). We stacked the images with good conditions. We did not detect any
uncatalogued sources within the BAT error region (Bernardini et al., GCN
#30929). Also, we did not detect the possible optical counterpart reported
by Mondy, CrAO, AbAO observations (N. Pankov et al., GCN #30932). We
obtained the 5-sigma limits of the stacked images as follows.

T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
1.3 2021-10-10 12:00:19 540 g'>17.4, Rc>17.5, Ic>16.3
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time

We used PS1 catalog for flux calibration.
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, Vol.73, Issue 1, Pages 4-24;
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