GCN Circular 31889
Subject
GRB 220412B: MITSuME Akeno optical upper limits
Date
2022-04-13T05:34:06Z (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 220412B (Gropp et al. GCN Circular #31886)
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 18:28:16 UT (82 minutes after the Swift/BAT
trigger). We stacked the images with good conditions. We did not detect any
uncatalogued sources within the BAT error region (Gropp et al. GCN Circular
#31886). We obtained the 5-sigma limits of the stacked images as follows.
T0+[min] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
82 2022-04-12 18:55:21 2820 g'>17.9, Rc>19.0, Ic>18.5
------------------------------------------------------------------------------------------------
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).