{
  "submittedHow": "web",
  "format": "text/plain",
  "body": "H. Negoro, M. Nakajima, K. Saito (Nihon U.), T. Usuki (Ehime U.),\nK. Takagi, H. Nishio (Nihon U.), T. Mihara, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), \nT. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, Y. Kondo, D. Iijima, A. Yoshida (AGU), \nY. Tsuboi, H. Sugai, N. Nagashima, Y. Ishihara (Chuo U.), M. Shidatsu, C. Kang, T. Nakamoto, \nM. Uenishi, S. Yatsuzuka (Ehime U.),I. Takahashi, Y. Yatsu (Science Tokyo), \nS. Nakahira, S. Ueno, H. Tomida, S. Ogawa, M. Kurihara (JAXA),\nY. Ueda, K. Fujiwara, S. Kobayashi (Kyoto U.), M. Yamauchi, M. Nishio, C. Hiraizumi (Miyazaki U.), \nK. Yamaoka (Nagoya U.), M. Sugizaki (Kanazawa U.), W. Iwakiri (Chiba U.), T. Kawamuro (Osaka U.), \nand S. Yamada (Tohoku U),\n\nThe MAXI/GSC nova alert system triggered on a bright uncatalogued hard X-ray transient source\nat 08:47:33 UT on February 6, 2026.\nAssuming that the source flux was constant over the transit,\nwe obtain the source position at\n(R.A., Dec) = (78.322 deg, -40.534 deg) = (05 13 17, -40 32 02) (J2000) \nwith a statistical 90% C.L. elliptical error region \nwith long and short radii of 0.33 deg and 0.23 deg, respectively. \nThe roll angle of the long axis from the north direction is 38.0 deg counterclockwise. \nThere is an additional systematic uncertainty of 0.1 deg (90% containment radius).\nWithout assumptions on the source constancy, we obtain a rectangular error\nbox for the transient source with the following corners:\n(77.845, -39.759) deg = (05 11 22, -39 45 32) (J2000)\n(77.278, -40.246) deg = (05 09 06, -40 14 45) (J2000)\n(79.005, -41.397) deg = (05 16 01, -41 23 49) (J2000)\n(79.569, -40.903) deg = (05 18 16, -40 54 10) (J2000)\nThe X-ray flux averaged over the scan was 244 +- 33 mCrab\n(4.0-10.0keV, 1 sigma error).\nThere was no significant excess flux in the previous transit at 07:36 UT \nand in the next transit at 10:22 UT with an upper limit of 20 mCrab for each.\n\nWe note that the X-ray burster 4U 0513-40 is close to the above position, but out of the error box.\nIf the systematic error is large this time, the burst may come from 4U 0513-40.\n",
  "bibcode": "2026GCN.43624....1N",
  "createdOn": 1770376491294,
  "circularId": 43624,
  "subject": "GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection",
  "submitter": "Hitoshi Negoro at Nihon University/MAXI team <negoro.hitoshi@nihon-u.ac.jp>",
  "eventId": "GRB 260206A"
}