{
  "bibcode": "2023GCN.33760....1N",
  "subject": "GRB 230510B: MAXI/GSC detection",
  "circularId": 33760,
  "createdOn": 1683761347062,
  "eventId": "GRB 230510B",
  "body": "M. Nakajima (Nihon U.), Y. Kawakubo (LSU), S. Sugita, M. Serino (AGU),\nH. Negoro, 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, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU),\nY. Tsuboi, S. Urabe, S. Nawa, N. Nemoto (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, T. Kurihara (JAXA),\nY. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani (Kyoto U.),\nM. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.),\nK. Yamaoka (Nagoya U.),\nM. Sugizaki (NAOC),\nW. Iwakiri (Chiba U.)\nreport on behalf of the MAXI team:\n\nThe MAXI/GSC nova alert system triggered a bright uncatalogued X-ray\ntransient source at  21:22:03 UT 10 May 2023.\nAssuming that the source flux was constant over the transit,\nwe obtain the source position at\n(R.A., Dec) = (0.692 deg, 27.541 deg) = (00 02 46, +27 32 27) (J2000)\nwith a statistical 90% C.L. elliptical error region\nwith long and short radii of 0.15 deg and 0.14 deg, respectively.\nThe roll angle of long axis from the north direction is 139.0 deg\ncounterclockwise.\nWithout assumptions on the source constancy, we obtain a rectangular error\nbox for the transient source with the following corners:\n(R.A., Dec) = (0.127, 28.437) deg = (00 00 30, +28 26 13) (J2000)\n(R.A., Dec) = (359.878, 28.290) deg = (23 59 30, +28 17 23) (J2000)\n(R.A., Dec) = (0.966, 26.843) deg = (00 03 51, +26 50 34) (J2000)\n(R.A., Dec) = (1.213, 26.988) deg = (00 04 51, +26 59 16) (J2000)\nThere is an additional systematic uncertainty of 0.1 deg (90%\ncontainment radius).\nThe trigger time and position was consistent with that of GRB 230510B\n(Fermi GBM, GCN 33759)\nThe X-ray flux averaged over the scan was 635 +- 75 mCrab\n(4.0-10.0keV, 1 sigma error).\nThere was no significant excess flux in the previous transit at 19:49 UT\nand in the next transit at 22:54 UT with an upper limit of 20 mCrab for each.\n",
  "submitter": "Satoshi Sugita at Aoyama Gakuin U. <sugita@phys.aoyama.ac.jp>"
}