Gamma-ray Burst 190117A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #23764
  K. Hurley, on behalf of the IPN,
  I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team,
  D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova and T. Cline on behalf of the Konus-Wind team,
  A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
  S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team,
  S. Xiao, C. K. Li, X. B. Li, Y. Huang, and S. L. Xiong on behalf of the Insight-HXMT GRB team,
  and
  W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report:
  The long-duration GRB 190117A was detected by AGILE (MCAL; Ursi, et al., GCN Circ. 23752), Insight (HXMT/HE; Xiao et al., GCN Circ. 23759), Konus-Wind, INTEGRAL (SPI-ACS), and Swift (BAT), at about 52607 s UT (14:36:47). The burst was outside the coded field of view of the BAT.
  We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:

    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     113.864 (07h 35m 27s)  +6.519 ( +6d 31' 10")
    Corners:
     113.942 (07h 35m 46s)  +8.247 ( +8d 14' 49")
     113.615 (07h 34m 28s)  +5.249 ( +5d 14' 56")
     113.807 (07h 35m 14s)  +4.881 ( +4d 52' 52")
     114.126 (07h 36m 30s)  +7.833 ( +7d 49' 58")
    ---------------------------------------------
  

  The error box area is about 2453 sq. arcmin, and its maximum dimension is 3.369 deg (the minimum one is 13.68 arcmin). The Sun distance was about 163 deg.
  This box may be improved.
  A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB190117_T52611/IPN
  The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
• GCN Circular #23782
  D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
  The long GRB 190117A (Agile/MCAL detection: Ursi et al., GCN 23752; Insight-HXMT/HE detection: Xiao et al., GCN 23759, IPN triangulation: Hurley et al., GCN 23764) triggered Konus-Wind (KW) at T0=52611.684 s UT (14:36:51.684).
  The burst light curve shows a weak emission pulse at ~T0-10 s and three bright pulses in the interval from ~T0 to ~T0+30 s. A total duration of the burst (T100) is ~36.3 s. The emission is seen up to ~15 MeV.
  As observed by Konus-Wind, the burst had a fluence of (4.1 ± 0.3)x10^-5 erg/cm2 and a 64-ms peak energy flux, measured from T0+1.984, of (1.66 ± 0.13)x10^-5 erg/cm2 (both in the 20 keV - 10 MeV energy range).
  The time-integrated spectrum (measured from T0 to T0+33.024 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -1.19 (-0.08,+0.07), the high energy photon index beta = -2.67 (-0.60,+0.27), the peak energy Ep = 190 (-17,+18) keV (chi2 = 90/97 dof).
  The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: alpha = -1.04 (-0.08,+0.07), beta = -2.68 (-0.44,+0.23), Ep = 208 (-18,+20) keV (chi2 = 74/97 dof).
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB190117_T52611/
  All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.
• GCN Circular #23792
  T. Khanam, V. Sharma, D. Bhattacharya and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
  Analysis of AstroSat CZTI data showed the detection of a long GRB 190117A, which was also detected by AGILE (MCAL; Ursi, et al., GCN Circ. 23752), Insight (HXMT/HE; Xiao et al., GCN Circ. 23759), Konus-Wind, INTEGRAL (Frederiks D. et al., GCN Circ 23782), IPN Triangulation (Hurley K. et al., GCN Circ. 23764) and Swift (BAT).
  The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 14:36:49.5 UT. The measured peak count rate is 2356 cts/s above the background in combined data of four quadrants, with a total of 11729 cts. The local mean background count rate was 524 cts/s. Using cumulative rates, we measure a T90 of 22.75 s. In preliminary analysis, we find that 862 Compton events are associated with this event.
  It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
  CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.