Gamma-ray Burst 180317A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #22521
  D.Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova, and T. Cline on behalf of the Konus-Wind team,
  K. Hurley, on behalf of the IPN,
  S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, and
  A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report:
  The short-duration GRB 180317A has been detected by Konus-Wind, INTEGRAL(SPI-ACS), and Swift(BAT) at about 61285 s UT (17:01:25). 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:
      92.196 (06h 08m 47s) +23.164 (+23d 09' 50")
    Corners:
      92.178 (06h 08m 43s) +21.042 (+21d 02' 32")
      92.100 (06h 08m 24s) +23.291 (+23d 17' 27")
      92.237 (06h 08m 57s) +25.258 (+25d 15' 28")
      92.293 (06h 09m 10s) +23.037 (+23d 02' 13")
    ---------------------------------------------
  

  The error box area is 1373 sq. arcmin, and its maximum dimension is 4.22 deg (the minimum one is 10.2 arcmin). The Sun distance was 94 deg.
  This box may be improved.
  A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB180317_T61287/IPN
  The time history and spectrum will be given in forthcoming GCN Circulars.
• GCN Circular #22552
  D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report:
  The short-duration, hard-spectrum GRB 180317A (IPN triangulation: Svinkin et al., GCN 22521) triggered Konus-Wind at T0=61287.097 s UT (17:01:27.097).
  The burst light curve shows a single pulse which starts at T0-34 ms and has a total duration of ~74 ms.
  As observed by Konus-Wind, the burst had a fluence of 9.47(-2.14,+6.93)x10^-7 erg/cm2, and a 16-ms peak flux, measured from T0-0.024 s, of 2.69(-0.71,+2.00)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  Since the most intense part of the burst was detected before the trigger, the spectral analysis was performed using the KW 3-channel light curve data.
  Modeling the KW 3-channel time-integrated spectrum (from T0-0.034 s to T0+0.040 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -0.74(-0.36,+0.51), and Ep = 757(-253,+1050) keV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180317_T61287/
  The burst is not seen in the waiting mode data.
  All the quoted errors are at the 68% confidence level. All the quoted values are preliminary.