Gamma-ray Burst 000801

On August 1, 2000 at 04:56:14 UT a burst was detected by Ulysses, Konus-Wind, and NEAR.

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN notice #761
  K. Hurley, on behalf of the Ulysses GRB team, S. Golenetskii and E. Mazets, on behalf of the Konus-Wind GRB team, and T. Cline, on behalf of the NEAR and Konus-Wind GRB teams, report:
  Ulysses, Konus, and NEAR observed this burst at 17774 s UT. As observed by Ulysses, it had a duration ~30 s, a 25-100 keV fluence of ~1.7x10^-5 erg/cm^2, and a peak flux over 0.25 s of ~1.3x10^-6 erg/cm^2 s. We have triangulated it to two preliminary, 3 sigma error boxes whose coordinates are:

      RA(2000)                 DEC(2000)
    6 h 27 m 31.87 s    -38 o 40 '   9.79 "  (CENTER)
    6 h 27 m 23.28 s    -38 o 42 '  48.54 "  (CORNER)
    6 h 27 m 31.98 s    -38 o 28 '  57.97 "  (CORNER)
    6 h 27 m 32.02 s    -38 o 51 '  21.61 "  (CORNER)
    6 h 27 m 40.45 s    -38 o 37 '  31.22 "  (CORNER)
  
                OR  
  
      RA(2000)                 DEC(2000)
   11 h 11 m 46.14 s     -9 o 24 '  43.65 "  (CENTER)
   11 h 11 m 58.39 s     -9 o 25 '  33.33 "  (CORNER)
   11 h 11 m 15.51 s     -9 o 16 '  27.89 "  (CORNER)
   11 h 12 m 16.65 s     -9 o 33 '   1.31 "  (CORNER)
   11 h 11 m 33.90 s     -9 o 23 '  54.23 "  (CORNER)
  

  This triangulation result can be improved. In particular, we have used Earth-blocking by BeppoSAX, which did not observe this event, to determine that the first position is the more likely one. However, confirmation will only come when the full Konus data set becomes available. Due to continuing network problems at Goddard, this may require up to 24 hours.
• GCN notice #762
  K. Hurley reports:
  In GCN 761, I inadvertently left out the error box areas: each error box is ~40 sq. arcmin.
• GCN notice #763
  T. Cline, on behalf of the Konus-Wind and NEAR GRB teams, S. Golenetskii and E. Mazets, on behalf of the Konus-Wind GRB team, and K. Hurley, on behalf of the Ulysses GRB team, report:
  Analysis of Konus-Wind data for this burst (GCN 761, 762) indicates that the correct error box of the two is:

      RA(2000)                 DEC(2000)
   11 h 11 m 46.14 s     -9 o 24 '  43.65 "  (CENTER)
   11 h 11 m 58.39 s     -9 o 25 '  33.33 "  (CORNER)
   11 h 11 m 15.51 s     -9 o 16 '  27.89 "  (CORNER)
   11 h 12 m 16.65 s     -9 o 33 '   1.31 "  (CORNER)
   11 h 11 m 33.90 s     -9 o 23 '  54.23 "  (CORNER)
  

• GCN notice #765
  E. Berger (Caltech), K. M. Becker (Oberlin), and D. A. Frail (NRAO) report on behalf of a larger collaboration:
  Beginning on August 1.98 UT we used the VLA at 4.86 GHz to observe the updated IPN error region of GRB000801 (GCN #763). We find no sources brighter than a 4-sigma level of approximately 200 microJy inside the error region. Further observations are planned.
• GCN notice #767
  E. Palazzi, N. Masetti (ITESRE, CNR, Bologna), E. Pian (OATs, Trieste), E. Rol, E.P.J. van den Heuvel (Univ. of Amsterdam), J.P.U. Fynbo (Univ. of Copenhagen), A.J. Castro-Tirado (LAEFF, IAA), J. Greiner (AIP), C. Kouveliotou (USRA), C. Lidman (ESO), on behalf of a larger collaboration, report:
  We obtained optical R-band images on three different positions at two different epochs each in order to mosaic the IPN error box (Cline et al., GCN #763) of GRB000801 (Hurley et al., GCN #761, #762) between 2000 Aug 2.972 and Aug 7.976 UT with Antu (VLT-UT1) plus FORS1 at ESO - Paranal (Chile). This mosaic covered 98% of the IPN error box (see the page on GRB000801 at http://www.mpe.mpg.de/~jcg/grb.html).
  The following table contains the main information on each pointing of the mosaic:

     pointing    mid-exp date   hours    exptime   seeing  limiting R mag
                     (UT)     after GRB   (sec)     (")      (3-sigma)
    ----------------------------------------------------------------------
    central       Aug 2.972      42.4      360      1.0         24.4
    southeastern  Aug 2.981      42.6      360      1.0         24.5
    northwestern  Aug 2.991      42.8      360      1.0         24.5
    central       Aug 3.986      66.7      240      0.8         24.4
    southeastern  Aug 3.992      66.9      190      0.8         24.0
    northwestern  Aug 7.976     162.5      600      0.9         24.7
  

  Photometric calibration was performed using standard stars in the Landolt field PG1657+078 (Landolt 1992, AJ 104, 340). The comparison between pairs of images does not reveal any object with significant brightness variation down to a 3-sigma limiting R magnitudes 24.4, 24.0 and 24.5 over the central, southeastern and northwestern parts of the GRB error box, respectively.
  
  
• GCN notice #768
  S. Sinha, P. Sreekumar, K. Kasturirangan, on behalf of SROSS C-2 (INDIAN GRB EXPERIMENT) team report:
  SROSS C-2 observed this burst at 17776.64 s UT (this time may be off by a few hundred ms). As observed by SROSS C-2, it had a duration (T90) of 13.9 secs, a 20-1024 keV fluence (not corrected for the sec (theta) factor) equal to 1.6.10-5 +-8.7.10-6 ergs cm-2. The peak flux (256 ms) in 20-100 keV band is 4.25 photons cm-2 s-1 and the peak flux (256 ms) in 100-1024 kev band is 4.45 photons cm-2 sec-1. The hardness ratio for this burst is equal to 0.27 +-0.08. Our hardness ratio is defined as counts(100-1024 keV)/counts(20-100 kev).
• GCN notice #773
  S.Sinha, P.Sreekumar, K.Kasturirangan, on behalf of SROSS C-2 (INDIAN GRB EXPERIMENT) team report:
  The hardness ratios (during the peak of the bursts) for GRB000801 and GRB000730 were reported by us to be 0.27+-0.08 and 0.47 +-0.082 respectively. Our hardness ratio is defined as [counts(100-1024 keV)/counts(20-100 keV)].
  For twenty-one SROSS C-2 GRBs that are common with BATSE, we find the mean hardness ratio to be 0.97 +- 0.079 and the standard deviation of this distribution is 0.37. The hardness ratios for the GRB000801 (GCN 768) and GRB000730 (GCN 772) may be interpreted on the basis of above mentioned data.