{
  "bibcode": "2021GCN.29282....1U",
  "body": "R. Uematsu (Kyoto U.), H. Negoro (Nihon U.), M. Serino (AGU), \nM. Nakajima, M. Aoki, K. Kobayashi, R. Takagi, K, Asakura, K, Seino (Nihon U.),\nT. Mihara, T. Tamagawa, M. Matsuoka (RIKEN),\nT. Sakamoto, S. Sugita, H. Nishida, K. Komachi, A. Yoshida (AGU),\nY. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.),\nM. Shidatsu (Ehime U.), N. Kawai, R. Adachi, M. Niwano, R. Hosokawa (Tokyo Tech),\nS. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA),\nY. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake, U. Goto (Kyoto U.),\nH. Tsunemi (Osaka U.), M. Yamauchi, K. Kurogi, K. Miike (Miyazaki U.), T. Kawamuro (NAOJ),\nK. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) \nreport on behalf of the MAXI team:\n\nThe MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient source \nat UT 09:03:26 on 2021 January 9.\nAssuming that the source flux was constant over the transit,\nwe obtain the source position at\n(R.A., Dec) = (62.003 deg, 4.679 deg) = (04 08 00, +04 40 44) (J2000) \nwith a statistical 90% C.L. elliptical error region \nwith long and short radii of 0.28 deg and 0.25 deg, respectively. \nThe roll angle of the long axis from the north direction is 58.0 deg counterclockwise. \nWithout assumptions on the source flux constancy, we obtain a rectangular error box\nfor the transient source with the following corners:\n(60.844, 3.548) deg = (04 03 22, +03 32 52) (J2000) \n(61.261, 3.251) deg = (04 05 02, +03 15 03) (J2000) \n(62.919, 5.559) deg = (04 11 40, +05 33 32) (J2000) \n(62.501, 5.857) deg = (04 10 00, +05 51 25) (J2000) \nThere is an additional systematic uncertainty of 0.1 deg (90% containment radius).\n\nThe X-ray flux averaged over the scan was 108 +- 23 mCrab\n(4.0-10.0keV, 1 sigma error).\nThere was no significant excess flux in the previous transit at UT 07:30\nand in the next transit at 10:36 with an upper limit of 20 mCrab for each.",
  "circularId": 29282,
  "createdOn": 1610194911000,
  "email": "negoro.hitoshi@nihon-u.ac.jp",
  "subject": "GRB 210109A: MAXI/GSC detection",
  "submitter": "Hitoshi Negoro at Nihon U  <negoro.hitoshi@nihon-u.ac.jp>",
  "eventId": "GRB 210109A"
}