GRB211218A

This page lists all entries on GRB211218A in GRBweb

Summary GCN 31261 GCN 31278

Summary table
Variable Value Source
T0 1:01:29 UTC GCN_circulars,MAXI Det
ra 137.2780° GCN_circulars,MAXI Det
decl -4.1100° GCN_circulars,MAXI Det
GBM_located False
mjd 59566.04269675926 GCN_circulars,MAXI Det
GCN 31261 table
GRB_name GRB211218A
GCN_number 31261
Detection_method MAXI Det
t_trigger 1:01:29 UTC
ra 137.2780°
decl -4.1100°
Circular_text TITLE: GCN CIRCULAR NUMBER: 31261 SUBJECT: GRB 211218A, MAXI J0909-041: MAXI/GSC detection DATE: 21/12/18 05:17:50 GMT FROM: Hitoshi Negoro at Nihon U R. Uematsu (Kyoto U.), H. Negoro (Nihon U.), M. Serino (AGU), M. Nakajima, K. Kobayashi, K. Asakura, K. Seino (Nihon U.), T. Mihara, T. Tamagawa, J. Li, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, K. Komachi, H. Hiramatsu, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu, M. Iwasaki (Ehime U.), N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka, M. Kurihara (JAXA), Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake, Y. Goto, K. Inaba (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, Y. Nonaka, T. Sato, R. Hatsuda, R. Fukuoka (Miyazaki U.), T. Kawamuro (UDP/NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 01:01:29 UT 2021 December 18. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (137.278 deg, -4.110 deg) = (09 09 06, -04 06 36) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.42 deg and 0.38 deg, respectively. The roll angle of long axis from the north direction is 62.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 118 +- 31 mCrab (4.0-10.0keV, 1 sigma error). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners: (R.A., Dec) = (135.984, -5.236) deg = (09 03 56, -05 14 09) (J2000) (R.A., Dec) = (136.566, -5.656) deg = (09 06 15, -05 39 21) (J2000) (R.A., Dec) = (138.302, -3.262) deg = (09 13 12, -03 15 43) (J2000) (R.A., Dec) = (137.722, -2.843) deg = (09 10 53, -02 50 34) (J2000) There was no significant excess flux in the previous transit at 12/17 23:28 UT and in the next transit at 12/18 02:34 UT with an upper limit of 20 mCrab for each. Finally, we note that due to the poor statistics, we can not confirm that this event is a GRB. Therefore, we also name the source MAXI J0909-041.
GCN 31278 table
GRB_name GRB211218A
GCN_number 31278
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 31278 SUBJECT: GRB 211218A: MITSuME Akeno optical upper limits DATE: 21/12/22 11:58:51 GMT FROM: Yuri Imai at Tokyo Inst of Tech 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).