GCN Circular 46222
Subject
GRB 261110A : MITSuME Akeno optical upper limits
Event
Date
2026-11-11T07:29:52Z (15 hours ago)
From
J. Yonamine at Institute of Science Tokyo <yonamine.j.21c9@m.isct.ac.jp>
Via
Web form
J. Yonamine, I. Takahashi, M. Sasada, H. Hagio, A. Ochi, Y. Kubo, R. Kato, N. Hosoya, Y. Yatsu and N. Kawai (Science Tokyo) report on behalf of the MITSuME collaboration:
We observed the field of GRB 261110A detected by SVOM/ECLAIRs (Wang et al., GCN 46215) with the optical three-color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50-cm telescope Akeno.
The observation started at 2026-11-10 11:58:39 UT (8.7 min after the trigger). We stacked the images taken under good conditions. We did not detect any optical point source at the reported position (Wu et al., GCN 46218; Li et al., GCN 46219; Moskvitin et al., GCN 46220). We obtained 5-sigma detection limits of the stacked images as follows.
T0+[sec] | MID-UT | T-EXP[sec] | 5-sigma limits
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929 | 2026-11-10 12:05:29 | 600 | g'>19.4, Rc>19.5, Ic>18.6
2311 | 2026-11-10 12:28:31 | 3000 | g'>20.2, Rc>20.3, Ic>19.3
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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; https://github.com/MNiwano/Eclaire).