GCN Circular 31278
Subject
GRB 211218A: MITSuME Akeno optical upper limits
Date
2021-12-22T11:58:51Z (3 years ago)
From
Yuri Imai at Tokyo Inst of Tech <imai@hp.phys.titech.ac.jp>
Y. Imai, R. Hosokawa, K. L. Murata, M. Niwano, Y. Takamatsu, N. Ito,
R. Yamaguchi, R. Noto, S. Sato, M. Takaku, Y. Yatsu, and N. Kawai
(TokyoTech) report on behalf of the MITSuME collaboration:
We performed tiling observations for the MAXI/GSC error region of GRB
211218A, MAXI J0909-041 (R. Uematsu et al. GCN Circular #31261, V.
Lipunov et al. GCN Circular #31260) with an optical tri-color (g', Rc,
and Ic) camera attached to the MITSuME 50 cm telescope Akeno.
The follow up observation started at 2021-12-18 13:35:14 UT, 12.6
hours after the trigger.
Our tiling observation covered almost ~70% of the MAXI/GSC error
region (GCN Circular #31261). Comparing our co-added images with the
GSC2.3 catalog, we found no optical transients in the observed region.
The 5-sigma upper limits of the co-added images are listed below.
Field num. | center position(R.A., Dec.) | size of field(R.A.(arcmin)
x Dec.(arcmin)) | 5-sigma upper limit | MID-UT(UT) | exposure
time(sec)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Field 00 | 9:08:47, -4:06:36 | 27.1 x 24.7 | g'>18.2, Rc>19.0, Ic>18.7
| 2021-12-18 17:57:09 | 360.0
Field 01 | 9:08:01, -4:22:05 | 26.6 x 26.5 | g'>18.3, Rc>19.1, Ic>18.7
| 2021-12-18 17:19:28 | 390.0
Field 02 | 9:09:42, -4:17:55 | 26.4 x 26.5 | g'>18.2, Rc>19.0, Ic>18.6
| 2021-12-18 17:45:57 | 330.0
Field 03 | 9:09:01, -4:31:20 | 27.4 x 24.2 | g'>18.2, Rc>19.0, Ic>18.6
| 2021-12-18 17:37:16 | 330.0
Field 04 | 9:07:45, -3:55:46 | 26.0 x 24.3 | g'>18.3, Rc>19.2, Ic>18.8
| 2021-12-18 16:58:53 | 450.0
Field 05 | 9:07:04, -4:08:57 | 26.5 x 27.5 | g'>17.9, Rc>18.7, Ic>18.4
| 2021-12-18 15:49:39 | 240.0
Field 06 | 9:09:26, -3:51:26 | 26.2 x 25.5 | g'>18.2, Rc>18.9, Ic>18.6
| 2021-12-18 17:24:50 | 360.0
Field 07 | 9:07:20, -4:34:20 | 26.5 x 26.1 | g'>18.0, Rc>18.7, Ic>18.4
| 2021-12-18 17:04:52 | 240.0
Field 08 | 9:10:28, -4:03:20 | 26.6 x 26.5 | g'>18.3, Rc>19.2, Ic>18.8
| 2021-12-18 16:49:06 | 540.0
Field 09 | 9:08:17, -4:47:13 | 26.4 x 26.7 | g'>18.1, Rc>18.9, Ic>18.5
| 2021-12-18 17:33:11 | 300.0
Field 10 | 9:08:29, -3:40:30 | 26.5 x 25.1 | g'>18.3, Rc>19.0, Ic>18.7
| 2021-12-18 17:11:30 | 390.0
Field 11 | 9:06:22, -4:25:47 | 25.8 x 26.1 | g'>18.2, Rc>19.1, Ic>18.7
| 2021-12-18 16:00:21 | 480.0
Field 12 | 9:10:10, -3:37:09 | 26.3 x 26.7 | g'>18.0, Rc>18.9, Ic>18.6
| 2021-12-18 16:24:58 | 300.0
Field 13 | 9:06:39, -4:50:05 | 26.4 x 26.6 | g'>17.9, Rc>18.8, Ic>18.4
| 2021-12-18 15:17:23 | 270.0
Field 14 | 9:11:06, -3:48:44 | 26.6 x 26.5 | g'>18.1, Rc>18.8, Ic>18.4
| 2021-12-18 17:11:04 | 210.0
Field 15 | 9:09:11, -3:27:56 | 26.0 x 26.9 | g'>18.1, Rc>19.0, Ic>18.6
| 2021-12-18 16:13:00 | 330.0
Field 16 | 9:07:35, -5:00:29 | 27.3 x 27.6 | g'>17.7, Rc>18.5, Ic>18.3
| 2021-12-18 15:36:49 | 180.0
Field 17 | 9:05:40, -4:40:29 | 27.2 x 26.4 | g'>18.0, Rc>18.8, Ic>18.6
| 2021-12-18 16:07:28 | 330.0
Field 18 | 9:10:52, -3:22:30 | 26.4 x 26.5 | g'>18.0, Rc>18.9, Ic>18.5
| 2021-12-18 15:30:13 | 300.0
Field 19 | 9:11:49, -3:34:14 | 26.6 x 26.5 | g'>18.0, Rc>18.7, Ic>18.4
| 2021-12-18 16:57:19 | 180.0
Field 20 | 9:05:56, -5:04:58 | 26.5 x 26.6 | g'>18.1, Rc>19.0, Ic>18.6
| 2021-12-18 17:02:01 | 420.0
Field 21 | 9:09:48, -3:03:38 | 28.5 x 28.6 | g'>17.1, Rc>17.8, Ic>17.4
| 2021-12-18 20:31:34 | 60.0
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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).