{
  "bibcode": "2021GCN.30113....1S",
  "body": "M. Serino, S. Sugita (AGU),\nH. Negoro, M. Nakajima, K. Kobayashi, K. Asakura, K. Seino (Nihon U.),\nT. Mihara, T. Tamagawa, M. Matsuoka (RIKEN),\nT. Sakamoto, K. Komachi, A. Yoshida (AGU),\nY. Tsuboi, W. Iwakiri, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.),\nM. Shidatsu (Ehime U.),\nN. Kawai, 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, Y. Goto, R. Uematsu (Kyoto U.),\nH. Tsunemi (Osaka U.),\nM. Yamauchi, Y. Nonaka, T. Sato, R. Hatsuda, R. Fukuoka (Miyazaki U.), T. Kawamuro (UDP/NAOJ),\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 \nX-ray transient source at 12:04:02 UT on 2021 June 2.\nAssuming that the source flux was constant over the transit,\nwe obtain the source position at\n(R.A., Dec) = (44.630 deg, -2.672 deg) = (02 58 31, -02 40 19) (J2000)\nwith a statistical 90% C.L. elliptical error region\nwith long and short radii of 0.17 deg and 0.16 deg, respectively.\nThe roll angle of long axis from the north direction is 107.0 deg counterclockwise.\nThere is an additional systematic uncertainty of 0.1 deg (90% containment radius).\nThe X-ray flux averaged over the scan was 393 +- 52 mCrab\n(4.0-10.0keV, 1 sigma error).\nWithout assumptions on the source constancy, we obtain a rectangular error\nbox for the transient source with the following corners:\n(R.A., Dec) = (43.754, -3.549) deg = (02 55 00, -03 32 56) (J2000)\n(R.A., Dec) = (44.013, -3.735) deg = (02 56 03, -03 44 05) (J2000)\n(R.A., Dec) = (45.446, -1.751) deg = (03 01 47, -01 45 03) (J2000)\n(R.A., Dec) = (45.187, -1.565) deg = (03 00 44, -01 33 53) (J2000)\nThere was no significant excess flux in the previous transit at 10:31 UT\nwith an upper limit of 20 mCrab.",
  "circularId": 30113,
  "createdOn": 1622637878000,
  "email": "serino@phys.aoyama.ac.jp",
  "subject": "GRB 210602A: MAXI/GSC detection",
  "submitter": "Motoko Serino at Aoyama Gakuin U.  <serino@phys.aoyama.ac.jp>",
  "eventId": "GRB 210602A"
}