Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 31757
SUBJECT: GRB 220311A: MITSuME Akeno optical upper limits
DATE: 22/03/15 02:22:55 GMT
FROM: Ryohei Hosokawa at Tokyo Institute of Technology
R. Hosokawa, Y. Imai, R. Yamaguchi, K. L. Murata, M. Niwano, N. Ito,
Y. Takamatsu, 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 220311A (The Fermi GBM team GCN Circular
#31740, V. Yurkov et al. GCN Circular #31741, V. Lipunov et al. GCN
Circular #31742, V. Lipunov et al. GCN Circular #31743, S.Mereghetti
et al. GCN Circular #31744, V. Lipunov et al. GCN Circular #31745)
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 2022-03-11 16:44:51 UT (11.7 minutes after
IBAS trigger). We stacked the images with good conditions. We did not
detect any uncatalogued sources within the IBAS error region
(S.Mereghetti et al. GCN Circular #31744). We obtained the 5-sigma
limits of the stacked images as follows.
T0+[min] MID-UT T-EXP[sec] 5-sigma limits
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29.0 2022-03-11 17:02:10 1440 g'>19.8, Rc>19.8, Ic>19.0
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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).
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