GCN Circular 31891
Subject
GRB 220412A: MITSuME Akeno optical upper limits
Date
2022-04-13T05:35:44Z (3 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
K. L. Murata, M. Niwano, Y. Imai, N. Ito, Y. Takamatsu, S. Sato, R.
Hosokawa, M. Sasada, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:
We observed the field of GRB 220412A (Klingler et al. GCN Circular #31881,
Watson et al. GCN Circular #31882, Breeveld and Klingler et al. GCN
Circular #31885, Evans et al. GCN Circular #31887, D'Ai et al. GCN Circular
#31888) 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 2022-04-12 10:10:00 UT (214 minutes after the
Swift/BAT trigger). We stacked the images with good conditions. We did not
detect any uncatalogued sources within the enhanced XRT error region (Evans
et al. GCN Circular #31887). We obtained the 5-sigma limits of the stacked
images as follows.
T0+[min] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
214 2022-04-12 10:53:37 3960 g'>19.0, Rc>19.3, Ic>18.8
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used the 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; https://github.com/MNiwano/Eclaire).