Gamma-ray Burst 200615B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Notice
  

  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Tue 16 Jun 20 00:04:48 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:    15358751
  EVENT_RA:        153.35d {+10h 13m 24s} (J2000),
                   153.61d {+10h 14m 26s} (current),
                   152.72d {+10h 10m 53s} (1950)
  EVENT_DEC:        -4.83d {-04d 49' 36"} (J2000),
                    -4.93d {-04d 55' 43"} (current),
                    -4.58d {-04d 34' 43"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      189.0 +- 0.0 [mCrab]
  EVENT_DATE:      19015 TJD;   167 DOY;   20/06/15
  EVENT_TIME:      37825.00 SOD {10:30:25.00} UT
  EVENT_TSCALE:    1s
  EVENT_EBAND:     Low, 2-4 keV
  SUN_POSTN:        84.91d {+05h 39m 38s}  +23.35d {+23d 21' 12"}
  SUN_DIST:         72.65 [deg] 
  MOON_POSTN:       25.13d {+01h 40m 32s}   +5.31d {+05d 18' 51"}
  MOON_DIST:       128.69 [deg]
  MOON_ILLUM:      25 [%]
  GAL_COORDS:      246.80, 40.23 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      157.08,-14.77 [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:     Tue 16 Jun 20 00:05:08 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:    15358751
  EVENT_RA:        153.42d {+10h 13m 41s} (J2000),
                   153.68d {+10h 14m 43s} (current),
                   152.79d {+10h 11m 10s} (1950)
  EVENT_DEC:        -5.16d {-05d 09' 28"} (J2000),
                    -5.26d {-05d 15' 35"} (current),
                    -4.91d {-04d 54' 34"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      85.0 +- 0.0 [mCrab]
  EVENT_DATE:      19015 TJD;   167 DOY;   20/06/15
  EVENT_TIME:      37825.00 SOD {10:30:25.00} UT
  EVENT_TSCALE:    1s
  EVENT_EBAND:     Low, 2-4 keV
  SUN_POSTN:        84.91d {+05h 39m 38s}  +23.35d {+23d 21' 12"}
  SUN_DIST:         72.86 [deg] 
  MOON_POSTN:       25.13d {+01h 40m 32s}   +5.32d {+05d 18' 55"}
  MOON_DIST:       128.78 [deg]
  MOON_ILLUM:      25 [%]
  GAL_COORDS:      247.18, 40.06 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      157.27,-15.05 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient. 
  

• GCN Circular #27960
  K. Miike (Miyazaki U.), H. Negoro (Nihon U.), Y. Kawakubo (LSU), M. Nakajima, M. Aoki, K. Kobayashi, R. Takagi, K, Asakura, K, Seino, S. Mokumoto (Nihon U.), T. Mihara, C. Guo, Y. Zhou, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, R. Adachi, M. Niwano (Tokyo Tech), S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA), Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, K. Kurogi (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), M. Sugizaki (NAOC) report on behalf of the MAXI team:
  The MAXI/GSC nova alert system triggered on an uncatalogued X-ray transient source at 10:30:18 UT on 2020 June 15. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (153.421 deg, -5.158 deg) = (10 13 41, -05 09 28) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.34 deg and 0.3 deg, respectively. The roll angle of the long axis from the north direction is 180.0 deg counterclockwise. Without assumptions on the source flux constancy, we obtain a rectangular error box for the transient source with the following corners:

  (R.A., Dec) = (152.024, -3.311) deg = (10 08 05, -03 18 39) (J2000)
  (R.A., Dec) = (151.564, -3.753) deg = (10 06 15, -03 45 10) (J2000)
  (R.A., Dec) = (153.538, -5.793) deg = (10 14 09, -05 47 34) (J2000)
  (R.A., Dec) = (153.998, -5.350) deg = (10 15 59, -05 20 59) (J2000)
  

  There is an additional systematic uncertainty of 0.1 deg (90% containment radius) in both error regions.
  The X-ray flux averaged over the scan was 85 +- 19 mCrab (4.0-10.0keV, 1 sigma error).
  There was no significant excess flux in the previous transit at 08:57 UT and in the next transit at 12:03 UT with an upper limit of 20 mCrab for each.
• GCN Circular #27974
  S. Nakahira (RIKEN), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration:
  At 10:26:46.325 UTC on 15 June 2020, the CALET Gamma-ray Burst Monitor (CGBM) triggered on the long weak GRB 200615B (trigger 1276251981: http://cgbm.calet.jp/cgbm_trigger/flight/1276251981/index.html), which was also detected by the MAXI/GSC at T0(CGBM)+213 sec (Miike et al. 2020, GCN Circ. 27960). The burst signal was seen by all CGBM detectors.
  The burst light curve shows a multi-peaked structure which starts at T+3.8 sec and ends at T+48.8 sec. The T90 and T50 durations measured by the SGM data are 40.0 +- 6.3 sec and 28.0 +- 9.5 sec (40-1000 keV), respectively.
  The ground processed light curve is available at
  http://cgbm.calet.jp/cgbm_trigger/ground/1276251981/
  The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.