Gamma-ray Burst 111016B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #12452
  K. Hurley, on behalf of the Mars Odyssey and MESSENGER GRB teams,
  J. Goldsten, on behalf of the MESSENGER NS GRB team,
  I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team,
  S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
  S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team,
  D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, and W. Hajdas, on behalf of the RHESSI GRB team,
  W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report:
  The long-duration, intense GRB 111016B was observed by Konus-Wind, Mars Odyssey (HEND), MESSENGER (GRNS), RHESSI, and Swift (BAT) (outside the coded field of view) at 81700 s UT (22:41:40). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:

    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     290.499 (19h 22m 00s)  -4.578 ( -4d 34' 39")
    Corners:
     290.322 (19h 21m 17s)  -4.416 ( -4d 24' 56")
     290.513 (19h 22m 03s)  -4.048 ( -4d 02' 53")
     290.676 (19h 22m 42s)  -4.740 ( -4d 44' 24")
     290.487 (19h 21m 57s)  -5.119 ( -5d 07' 09")
    ---------------------------------------------
  

  The error box area is 696 sq. arcmin, and its maximum dimension is 64 arcmin.
  This box can be improved.
  The time history and spectrum will be given in a forthcoming GCN Circular.
• GCN Circular #12456
  S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
  The long hard intense GRB 111016B (localized by IPN: Hurley et al., GCN 12452) triggered Konus-Wind at T0=81700.723s UT (22:41:40.723)
  The light curve shows a multi-peaked complex with a total duration of ~150 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB111016_T81700/
  As observed by Konus-Wind the burst had a fluence of 1.37(-0.05,+0.05)x10-4 erg/cm2, and a 256-ms peak flux, measured from T0+1.792 s, of 3.7(-0.3,+0.3)x10-6 erg/cm2/s (both in the 20 keV - 5 MeV energy range).
  The time-integrated spectrum of the burst (measured from T0 to T0+145.408 s) is best fitted in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which alpha = -0.78 (-0.06, +0.06), and Ep = 378(-19, +21) keV, chi2 = 58.7/76 dof. Fitting this spectrum by the GRB (Band) function yields the same alpha and Ep with a high energy photon index beta < -3.0 (chi2 = 58.7/75 dof).
  The spectrum at the maximum count rate (measured from T0 to T0+6.144 s) is best fitted in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which

  alpha = -0.72 (-0.10, +0.11),
  and Ep = 327(-26, +30) keV,
  chi2 = 86.4/76 dof.
  

  All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.
• 1303.1564 from 8 Mar 13
  D. Zaborov et al.: The HAWC observatory as a GRB detector
  The High Altitude Water Cherenkov Observatory (HAWC) is an air shower array currently under construction in Mexico at an altitude of 4100 m. HAWC will consist of 300 large water tanks covering an area of about 22000 square meters and instrumented with 4 photomultipliers each. The experimental design allows for highly efficient detection of photon-induced air showers in the TeV and sub-TeV range and gamma-hadron separation. We show that HAWC has a reasonable chance to observe the high-energy power law components of GRBs that extend to 50 GeV. In particular, HAWC will be capable of observing events similar to GRB 090510 and GRB 090902B. The observations (or non-observations) of GRBs by HAWC will provide information on the high-energy spectra of GRBs. An engineering array consisting of 6 water tanks was operated at the HAWC site since September 2011, collecting 3 months of data. An upper limit on high energy emission from GRB 111016B is derived from these data.
• 1408.3477 from 18 Aug 14
  A. U. Abeysekara et al.: VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory
  VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB 111016B and GRB 120328B.