Gamma-ray Burst 180318A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

  • GCN Circular #22522
    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,
    S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer, on behalf of the Swift-BAT 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 180318A has been detected by Konus-Wind, Swift (BAT), and Mars-Odyssey (HEND), so far, at about 84000 s UT (23:20:00).
    We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:
       RA(2000), deg                 Dec(2000), deg
       180.343 (12h 01m 22s) +33.936 (+33d 56' 09")
       179.707 (11h 58m 50s) +32.043 (+32d 02' 35")
       181.324 (12h 05m 18s) +35.706 (+35d 42' 23")
       180.991 (12h 03m 58s) +35.829 (+35d 49' 46")
       179.386 (11h 57m 33s) +32.164 (+32d 09' 49")
    The error box area is 1.16 sq. deg, and its maximum dimension is 3.93 deg (the minimum one is 17.8 arcmin). The Sun distance was 144 deg.
    This box may be improved.
    A triangulation map is posted at
    The time history and spectrum will be given in forthcoming GCN Circulars.
  • GCN Circular #22554
    A. Tsvetkova, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A.Kozlova, and T. Cline on behalf of the Konus-Wind team, report:
    The long-duration GRB 180318A (IPN Triangulation: Hurley et al., GCN 22522) triggered Konus-Wind at T0=3D84002.795 s UT (23:20:02.795).
    The burst light curve shows two emission episodes with multipeaked=20 structure, which start at ~T0-53 s and have a total duration of ~280.0 s. The main episode lasts from ~T0-53 s to ~T0+30 s, the second episode lasts from ~T0+150 s to ~T0+200 s. The emission is seen up to 1.2 MeV.
    The Konus-Wind light curve of this GRB is available at
    As observed by Konus-Wind, the burst had a fluence of 1.13(-0.24,+0.23)x10^-4 erg/cm2, and a 64-ms peak energy flux, measured from T0+18.560 s, of 4.89(-1.04,+1.11)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
    The time-integrated spectrum of the burst (measured from T0 to T0+205.056 s) is best fit in the 20 keV - 1.2 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha =3D -0.89(-0.24,+0.31), the high energy photon index beta =3D -2.12(-0.48,+0.18), the peak energy Ep =3D 195(-45,+69) keV, chi2 =3D 83/59 dof.
    The spectrum near the maximum count rate (measured from T0+16.640 to T0+24.832 s) is best fit in the 20 keV - 1.2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with=A0 alpha =3D -0.98(-0.19,+0.22) and Ep =3D 251(-40,+63) keV (chi2 =3D 63/60 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and=A0 beta < -2.13 (chi2 =3D 62/59 dof)
    All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
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    Jochen Greiner, last update: 27-Mar-2018 [Disclaimer]