GCN Circular 32014
Subject
GRB 220506A: MITSuME Akeno optical upper limits
Date
2022-05-10T06:41:09Z (3 years ago)
From
Naohiro Ito at Tokyo Tech <n.ito@hp.phys.titech.ac.jp>
N. Ito, M. Sasada, Y. Imai, K. L. Murata, M. Niwano, Y. Takamatsu, S.
Sato, M. Tateda, T. Hattori, R. Hosokawa, Y. Yatsu, and N. Kawai
(Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 220506A (Urabe et al. GCN Circular
#32001, Evans et al. GCN Circular #32005, Osborne et al. GCN Circular
#32006, Hu et al. GCN Circular #32008, Swain et al. GCN Circular
#32012) 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
2022-05-06 13:00:47 UT (6.5 hours after the MAXI/GSC trigger). We
stacked the images with good conditions. Additionally, we performed
the other follow-up observation starting at 2022-05-09 16:12:56 UT. We
did not detect any uncatalogued sources within the XRT error region
(Osborne et al. GCN Circular #32006). We obtained the 5-sigma limits
of the stacked images as follows.
T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
8.2 2022-05-06 14:42:28 240 g'>16.9, Rc>17.0, Ic>16.6
34.2 2022-05-07 16:37:41 8580 g'>18.9, Rc>19.5, Ic>18.8
82.9 2022-05-09 17:21:47 6660 g'>19.0, Rc>19.4, Ic>19.0
------------------------------------------------------------------------------------------------
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).