Gamma-ray Burst 221028B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Notice
  

      
  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Fri 28 Oct 22 23:08:22 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:      9880665205
  EVENT_RA:        214.91d {+14h 19m 39s} (J2000),
                   215.26d {+14h 21m 02s} (current),
                   214.15d {+14h 16m 37s} (1950)
  EVENT_DEC:       -36.84d {-36d 50' 08"} (J2000),
                   -36.94d {-36d 56' 23"} (current),
                   -36.61d {-36d 36' 23"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      429.0 +- 0.0 [mCrab]
  EVENT_DATE:      19880 TJD;   301 DOY;   22/10/28
  EVENT_TIME:      75474.00 SOD {20:57:54.00} UT
  EVENT_TSCALE:    1s
  EVENT_EBAND:     Low, 2-4 keV
  SUN_POSTN:       213.21d {+14h 12m 51s}  -13.36d {-13d 21' 22"}
  SUN_DIST:         23.65 [deg]
  MOON_POSTN:      260.46d {+17h 21m 51s}  -26.33d {-26d 19' 46"}
  MOON_DIST:        39.53 [deg]
  MOON_ILLUM:      15 [%]
  GAL_COORDS:      321.95, 22.76 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      225.10,-21.58 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.
  

• GCN Notice
  

  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Fri 28 Oct 22 23:27:37 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:      9880665205
  EVENT_RA:        215.10d {+14h 20m 24s} (J2000),
                   215.45d {+14h 21m 47s} (current),
                   214.34d {+14h 17m 21s} (1950)
  EVENT_DEC:       -36.88d {-36d 52' 47"} (J2000),
                   -36.98d {-36d 59' 00"} (current),
                   -36.65d {-36d 39' 03"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      159.0 +- 0.0 [mCrab]
  EVENT_DATE:      19880 TJD;   301 DOY;   22/10/28
  EVENT_TIME:      75474.00 SOD {20:57:54.00} UT
  EVENT_TSCALE:    1s
  EVENT_EBAND:     Low, 2-4 keV
  SUN_POSTN:       213.22d {+14h 12m 54s}  -13.36d {-13d 21' 38"}
  SUN_DIST:         23.71 [deg]
  MOON_POSTN:      260.67d {+17h 22m 41s}  -26.36d {-26d 21' 22"}
  MOON_DIST:        39.54 [deg]
  MOON_ILLUM:      15 [%]
  GAL_COORDS:      322.08, 22.66 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      225.27,-21.57 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.
  

• GCN Circular #32882
  H. Negoro (Nihon U.), M. Serino (AGU), M. Shidatsu (Ehime U.), M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, J. Kohara, S. Urabe, S. Nawa, N. Nemoto (Chuo U.), M. Iwasaki (Ehime U.), N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, T. Kurihara (JAXA), Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba (Kyoto U.), M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) report on behalf of the MAXI team:
  The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 2022-10-28T20:57:52 UT. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (215.098 deg, -36.880 deg) = (14 20 23, -36 52 48) (J2000) with a 90% C.L. statistical error of 0.23 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 159 +- 26 mCrab (4.0-10.0keV, 1 sigma error). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners:

  (214.489, -35.809) deg = (14 17 57, -35 48 32) (J2000)
  (214.045, -36.075) deg = (14 16 10, -36 04 30) (J2000)
  (215.717, -37.852) deg = (14 22 52, -37 51 07) (J2000)
  (216.165, -37.579) deg = (14 24 39, -37 34 44) (J2000)
  

  There was no significant excess flux in the previous transit at 19:24 UT and in the next transit at 22:09 UT with an upper limit of 20 mCrab for each.