Gamma-ray Burst 150919A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #18355
  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,
  S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, 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, and
  W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report:
  A short-duration GRB 150919A has been detected by Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND), so far, at about 74595 s UT (20:43:15).
  We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:

  ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     132.960 (08h 51m 50s) +44.066 (+44d 03' 59")
    Corners:
     132.432 (08h 49m 44s) +43.742 (+43d 44' 33")
     132.726 (08h 50m 54s) +44.076 (+44d 04' 34")
     133.487 (08h 53m 57s) +44.379 (+44d 22' 43")
     133.193 (08h 52m 46s) +44.055 (+44d 03' 20")
    ---------------------------------------------
  

  The error box area is 412 sq. arcmin, and its maximum dimension is 59 arcmin (the minimum one is 11 arcmin). The Sun distance was 58 deg.
  This box may be improved.
  A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB150919_T74595/IPN/
  The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
• GCN Circular #18356
  S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report:
  The short-duration GRB 150919A (IPN triangulation: Hurley et al., GCN Circ. 18355) triggered Konus-Wind at T0=74595.399 s UT (20:43:15.399).
  The burst light curve shows a single pulse with a duration of ~0.2 s followed by a weak emission up to ~1.2 s. The emission is seen up to ~2 MeV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150919_T74595/
  As observed by Konus-Wind, the burst had a fluence of 1.46(-0.27,+0.33)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0 s, of 1.43(-0.44,+0.50)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-averaged spectrum of the burst (measured from T0 to T0+0.128 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.61(-0.34,+0.43) and Ep = 405(-114,+199) keV (chi2 = 22/25 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta <-1.8 (chi2 = 21/24 dof)
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.