GCN Circular 32320
Subject
GRB 220701A: MITSuME Akeno optical upper limits
Event
Date
2022-07-04T06:38:32Z (4 years ago)
From
Yutaka Takamatsu at Tokyotech <takamatsu@hp.phys.titech.ac.jp>
Y. Takamatsu, N. Ito, M. Niwano, Y. Imai, S. Sato, M. Tateda, N.
Higuchi, T. Hattori, R. Hosokawa, K. L. Murata, M. Sasada, Y. Yatsu,
and N. Kawai (Tokyo Tech) report on behalf of the MITSuME
collaboration:
We observed the field of GRB 220701A (P. A. Evans et al. GCN Circular
#32306 & #32308, B. O'Connor et al. GCN Circular #32309, S. R. Oates
et al. GCN Circular #32310, Y.-D. Hu et al. GCN Circular #32311, R.
Strausbaugh et al. GCN Circular #32313, J. D. Gropp et al. GCN
Circular #32314, WeiKang Zheng et al. GCN Circular #32315, S. Belkin
et al. GCN Circular #32317, Alan M. Watson et al. GCN Circular #32318)
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
2022-07-01 19:37:09 UT (884 minutes after the Swift/BAT trigger). We
stacked the images with good conditions. We did not detect any
uncatalogued sources within the enhanced Swift/BAT error region (Evans
et al. GCN Circular #32306). We obtained the 5-sigma limits of the
stacked images as follows.
T0+[days] | MID-UT | T-EXP[sec] | 5-sigma limits
------------------------------------------------------------------------------------------------
0.6 | 2022-07-01 14:31:19 | 9060 | g'>19.4, Rc>20.1, Ic>20.9
------------------------------------------------------------------------------------------------
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).