{
  "eventId": "GRB 231129B",
  "bibcode": "2023GCN.35214....1K",
  "subject": "GRB 231129B: MAXI/GSC detection",
  "submittedHow": "web",
  "submitter": "Motoko Serino at Aoyama Gakuin U. <serino@phys.aoyama.ac.jp>",
  "circularId": 35214,
  "body": "M. Kurihara (JAXA), H. Negoro (Nihon U.), M. Serino (AGU), W. Iwakiri (Chiba U.),\nM. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.), \nT. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), \nT. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), \nY. Tsuboi, S. Urabe, S. Nawa, N. Nemoto, E.Goto (Chuo U.), \nM. Shidatsu (Ehime U.),\nI. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech), \nS. Nakahira,  S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA), \nY. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani, Y. Okada (Kyoto U.), \nM. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.), \nK. Yamaoka (Nagoya U.),\nY. Kawakubo (LSU),\nM. Sugizaki (NAOC),\nreport on behalf of the MAXI team:\n\nThe MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 14:03:05 UT on 29 November 2023.\nAssuming that the source flux was constant over the transit,\nwe obtain the source position at\n(R.A., Dec) = (285.662 deg, 40.278 deg) = (19 02 38, +40 16 40) (J2000)\nwith a statistical 90% C.L. elliptical error region\nwith long and short radii of 0.39 deg and 0.26 deg, respectively.\nThe roll angle of long axis from the north direction is 75.0 deg counterclockwise.\nWithout assumptions on the source constancy, we obtain a rectangular error\nbox for the transient source with the following corners:\n(283.889, 39.749) deg = (18 55 33, +39 44 56) (J2000)\n(284.232, 39.302) deg = (18 56 55, +39 18 07) (J2000)\n(286.730, 40.399) deg = (19 06 55, +40 23 56) (J2000)\n(286.398, 40.853) deg = (19 05 35, +40 51 10) (J2000)\nThere is an additional systematic uncertainty of 0.1 deg (90% containment radius).\n\nThe X-ray flux averaged over the scan was 141 +- 32 mCrab\n(4.0-10.0keV, 1 sigma error).\nThere was no significant excess flux in the previous transit at 12:30 UT\nwith an upper limit of 20 mCrab.",
  "createdOn": 1701271420323
}