Gamma-ray Burst 151222A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #18720
  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,
  V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM 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:
  The short-duration, hard-spectrum GRB 151222A has been detected by Konus-Wind, Fermi (GBM: Hoi-Fung Yu GCN Circ. 18715), INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND), so far, at about 29414 s UT (08:10:14).
  We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:

    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     354.942 (23h 39m 46s) +34.095 (+34d 05' 44")
    Corners:
     355.188 (23h 40m 45s) +34.534 (+34d 32' 01")
     354.558 (23h 38m 14s) +33.943 (+33d 56' 34")
     354.701 (23h 38m 48s) +33.652 (+33d 39' 07")
     355.328 (23h 41m 19s) +34.244 (+34d 14' 39")
    ---------------------------------------------
  

  The error box area is 792 sq. arcmin, and its maximum dimension is 58 arcmin (the minimum one is 16.8 arcmin). The Sun distance was 98 deg.
  This box may be improved.
  A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB151222_T29415/IPN/
  The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
• GCN Circular #18723
  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, hard-spectrum GRB 151222A (Fermi GBM detection: Hoi-Fung Yu, GCN Circ. 18715; IPN triangulation: Hurley, et al., GCN Circ. 18720) triggered Konus-Wind at T0=29415.138 s UT (08:10:15.138).
  The burst light curve shows a double-peaked structure with a total duration of ~0.5 s.
  As observed by Konus-Wind, the burst had a fluence of 2.20(-0.23,+0.28)x10^-6 erg/cm2 and a 16-ms peak flux, measured from T0+0.048 s, of 1.03(-0.11,+0.13)x10^-5 erg/cm2/s (both in the 20 - 1500 keV energy range).
  Since a major fraction of the burst counts was accumulated before the trigger, the spectral analysis was performed using the KW 3-channel light curve data. Modeling the 3-channel time-integrated spectrum (measured from T0-0.434 s to T0+0.094 s) by the cutoff power law yields the following model parameters: the photon index alpha=0.13(-0.44,+0.64), and the peak energy Ep=625(-118,+220) keV.
  All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary.
  The K-W light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB151222_T29415/