Gamma-ray Burst 180116A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Notice
  

  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Tue 16 Jan 18 01:03:54 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:    134001745
  EVENT_RA:        215.66d {+14h 22m 37s} (J2000),
                   215.87d {+14h 23m 28s} (current),
                   215.07d {+14h 20m 17s} (1950)
  EVENT_DEC:       +18.96d {+18d 57' 32"} (J2000),
                   +18.88d {+18d 52' 39"} (current),
                   +19.19d {+19d 11' 09"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      609.0 +- 0.0 [mCrab]
  EVENT_DATE:      18134 TJD;    16 DOY;   18/01/16
  EVENT_TIME:      2250.00 SOD {00:37:30.00} UT
  EVENT_TSCALE:    1day
  EVENT_EBAND:     Low, 2-4 keV
  SUN_POSTN:       297.83d {+19h 51m 18s}  -20.98d {-20d 58' 30"}
  SUN_DIST:         89.56 [deg]
  MOON_POSTN:      285.38d {+19h 01m 32s}  -19.98d {-19d 58' 29"}
  MOON_DIST:        78.42 [deg]
  MOON_ILLUM:      1 [%]
  GAL_COORDS:       16.45, 67.53 [deg] galactic lon,lat of the burst (or transient)      
  ECL_COORDS:      206.11, 31.16 [deg] ecliptic lon,lat of the burst (or transient)      
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.
  

• GCN Circular #22347
  H. Kawai (Chuo U.), H. Negoro (Nihon U.), M. Serino (AGU), S. Nakahira (RIKEN), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai (JAXA), T. Mihara, M. Sugizaki, W. Iwakiri, M. Shidatsu, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), N. Kawai, S. Sugita, T. Yoshii, Y. Tachibana, S. Harita, Y. Muraki, K. Morita (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka, T. Hashimoto (AGU), H. Tsunemi, T. Yoneyama (Osaka U.), M. Nakajima, T. Kawase, A. Sakamaki (Nihon U.), Y. Ueda, T. Hori, A. Tanimoto, S. Oda, T. Morita, S. Yamada (Kyoto U.), Y. Tsuboi, Y. Nakamura, R. Sasaki, T. Sato (Chuo U.), M. Yamauchi, C. Hanyu, K, Hidaka (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.)
  report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 00:37:30 UT on 16 January 2018. Assuming that the source flux was constant over the transit, we obtain the source position at
  (R.A., Dec) = (215.655 deg, 18.959 deg) = (14 22 37, +18 57 32) (J2000)
  with a statistical 90% C.L. elliptical error region with long and short radii of 0.13 deg and 0.11 deg, respectively. The roll angle of long axis from the north direction is 158.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 609 +- 65 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:

  (R.A., Dec) = (214.873, 19.864) deg = (14 19 29, +19 51 48) (J2000)
  (R.A., Dec) = (214.781, 19.788) deg = (14 19 07, +19 47 16) (J2000)
  (R.A., Dec) = (216.314, 18.226) deg = (14 25 15, +18 13 31) (J2000)
  (R.A., Dec) = (216.405, 18.300) deg = (14 25 37, +18 18 01) (J2000)
  

  There was no significant excess flux in the previous transit at UT 23:04 with an upper limit of 20 mCrab.
• GCN Circular #22356
  M. Stanbro and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
  "At 00:36:52.81 UT on 16 January 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 180116A (trigger 537755817 / 180116026) which was also detected by the MAXI/GSC (H. Kawai et al. 2018, GCN 22347). The GBM on-ground location is consistent with the MAXI/GSC position.
  The angle from the Fermi LAT boresight at the GBM trigger time is 39 degrees.
  The GBM light curve consists of several episodes with a duration (T90) of about 60 s (50-300 keV). The time-averaged spectrum from T0-3.07 s to T0+58.37 s is best fit by a simple power law function with index -1.72 +/- 0.05.
  The event fluence (10-1000 keV) in this time interval is (3.54 +/- 0.28)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-1.47 s in the 10-1000 keV band is 1.98 +/- 0.24 ph/s/cm^2.
  The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
• GCN Circular #22361
  Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, Y. Kawakubo, M. Moriyama, Y. Yamada, A. Tezuka, S. Matsukawa (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration:
  The long-duration, soft and weak GRB 180116A (Kawai et al., GCN circ. 22347; Stanbro et al., GCN circ. 22356) was detected by the CALET Gamma-ray Burst Monitor (CGBM) in the survey mode. The burst signal is only seen below 100 keV in all CGBM instruments, confirming its soft nature.
  The light curve of the HXM shows several overlapping pulses. The emission starts at T-5 sec, peaks at T+11 sec and ends at T+47 sec, where T0 is the Fermi-GBM trigger time at 00:36:52.81 UT. The T90 and the T50 durations measured by the combined HXM data (HXM1+HXM2) are 46 +- 10 sec and 27 +- 10 sec (10-300 keV), respectively.
  The ground processed light curve is available at
  http://cgbm.calet.jp/cgbm_trigger/ground/1200098002/
  The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.