GCN Circular 31488
Subject
GRB 220117A: MITSuME Akeno optical upper limits
Date
2022-01-18T17:30:21Z (3 years ago)
From
Naohiro Ito at Tokyo Tech <n.ito@hp.phys.titech.ac.jp>
N. Ito, R. Hosokawa, K. L. Murata, M. Niwano, Y. Imai, Y. Takamatsu,
R. Yamaguchi, R. Noto, S. Sato, M. Takaku, Y. Yatsu, and N. Kawai
(Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 220117A (A. Melandri et al. GCN Circular
#31466, S.Y. Fu et al. GCN Circular #31467, V. Lipunov et al. GCN
Circular #31470, A.P. Beardmore et al. GCN Circular #31472, J.A.
Kennea et al. GCN Circular #31477, J. Palmerio et al. GCN Circular
#31480, R. Strausbaugh et al. GCN Circular #31481, A. A. Breeveld et
al. GCN Circular #31482, D. M. Palmer et al. GCN Circular #31485, P.
Veres et al. GCN Circular #31487) 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
2022-01-18 10:26:37 UT (18.1 hours after Swift trigger). We stacked
the images with good conditions. We did not detect any sources within
the XRT error region (A.P. Beardmore et al. GCN Circular #31472). We
obtained the 5-sigma limits of the stacked images as follows.
T0+[hours] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
21.3 2022-01-18 13:34:36 7740 g'>19.0, Rc>19.5, Ic>19.2
------------------------------------------------------------------------------------------------
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; https://github.com/MNiwano/Eclaire).