Gamma-ray Burst 000307

On March 7, 2000, 21:50:47 UT Earth-crossing time, a GRB was detected by Ulysses, BATSE (#8022), NEAR and Konus.

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN notice #601
  K. Hurley, T. Cline, C. Kouveliotou, R. M. Kippen, E. Mazets, and S. Golenetskii, on behalf of the Ulysses, NEAR, BATSE, and Konus GRB teams, report:
  Ulysses, NEAR, BATSE, and Konus observed GRB000307 (BATSE #8022) at 78647 s UT. As observed by Ulysses, this burst had a 25-100 keV fluence of ~10^-6 erg/cm^2 and a T90 duration of ~20 s. We have triangulated this burst to an ~60 sq. arcmin. error box whose center and corners (3 sigma) are given by:

      RA(2000)                 DEC(2000)
    5 h 56 m 18.73 s      7 o 56 '  30.94 "  (CENTER)
    5 h 55 m 50.22 s      7 o 54 '   9.95 "  (CORNER)
    5 h 56 m 24.70 s      8 o  1 '  14.01 "  (CORNER)
    5 h 56 m 12.77 s      7 o 51 '  47.82 "  (CORNER)
    5 h 56 m 47.32 s      7 o 58 '  52.45 "  (CORNER)
  

  Some refinement to this position is possible.
• GCN notice #608
  A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
  We have acquired preliminary BVRcIc all-sky photometry for the field of GRB000307 with the USNOFS 1.0-m telescope on one photometric night. This 11x11arcmin field covers the IPN error box and extends a little fainter than V=20. All stars brighter than V=14 are saturated and should be used with care. We have placed the photometric data on our anonymous ftp site: ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb000307.dat. This file will be updated if an optical transient is discovered. The current photometry has a potential external zero-point error of about two percent.
  The astrometry in this file is based on linear plate solutions with respect to USNO-A2.0. The internal errors are less than 100mas.
• GCN notice #609
  J. Kemp & J. P. Halpern (Columbia U.) report on behalf of the MDM Observatory GRB follow-up team:
  We observed the entire IPN error box of GRB 000307 (Hurley et al. GCN #601) in the R band using the MDM 1.3m telescope starting on March 10.12 UT, and again on March 11.12 UT. One hour of exposure was obtained on each night in seeing of approximately 1".4. No new object is apparent above the limit of the digitized POSS-II plate, and no variable object is detected brighter than an approximate limiting magnitude of R = 21.7. These observations were severely affected by scattered light from the star Betelgeuse, which is only 0.6 degrees away, making precise photometry difficult. We also note that Galactic extinction in this direction is significant, with E(B-V) = 0.445 according to Schlegel et al. (1998), corresponding to A_R = 1.19.
• GCN/IPN/HUNTSVILLE LOCALIZATION
  

  TITLE:          GCN/IPN/HUNTSVILLE LOCALIZATION
  NOTICE_TYPE:    Updated (based on the BATSE-LOCBURST location)
  NOTICE_DATE:    Thu Mar  9 16:16:21 GMT 2000
  TRIGGER_NUM:    8022
  GRB_DATE:       00/03/07
  GRB_TIME:       21:50:47.03 UT
  BACO_RA:        82.35d {+05h 29m 23s}   (J2000)
  BACO_DEC:       +8.34d {+08d 20' 24"}
  HUNT_RA:        90.44d {+06h 01m 45s}   (J2000)
  HUNT_DEC:       6.44d {+06d 26' 40"}
  HUNT_ERR:       2.12 [degees radius, statistical plus systematic]
  B_H_DELTA:      8.26 [deg]
  HUNT_SC_AZ:     277.01 [deg]
  HUNT_SC_EL:     6.77 [deg]  {Zen_angle=83.23}
  SUN_POSTN:      348.63d {+23h 14m 31s}   -4.88d {-04d 53' 03"}   (Current)
  SUN_B_DIST:     94.38 [deg]
  MOON_POSTN:     9.53d {+00h 38m 08s}   -0.95d {-00d 57' 14"}   (Current)
  MOON_B_DIST:    73.15 [deg]
  ANNULUS_RA:     143.8556d {+09h 35m 25s}   (J2000)
  ANNULUS_DEC:    -42.4978d {-42d 29' 51"}
  ANNULUS_RADIUS: 70.850 [deg]
  ANNULUS_WIDTH:  0.173 [deg]  (Total width)
  COMMENTS:       Multi-peaked event, 4 peaks, duration about 40sec.
  COMMENTS:       Detected above 300keV.
  

  This IPN localization is preliminary. The "total width" of the annulus was selected to include all known uncertainties and systematics. The final analysis will reduce this width. All follow-up queries should be addressed to Kevin Hurley (UC Berkeley, khurley@sunspot.ssl.berkeley.edu).
  The center of the IPN annulus is tabulated below along the segment that intersects the Huntsville error circle. The Distance column is the sky-angle distance between the Huntville location and the sampled position on the arc segment. The position of maximum probability plus the 1-, 2-, & 3-sigma containment probabilities (statistical+systematic) are marked.
  A detailed description of the format, content, and meaning of this document is given in the URL: http://gcn.gsfc.nasa.gov/gcn/ipn.html
• GCN notice #617
  H. Pedersen, B. L. Jensen (University of Copenhagen), J. Gorosabel (Danish Space Research Institute, Copenhagen), J. P. U. Fynbo (Aarhus University) report on behalf of a wider, European group:
  We have observed the entire error box of GRB 000307 (cf. Hurley et al., GCN #601), using the WFI instrument attached to the 2.2-m ESO/MPI telescope at La Silla.
  The exposure dates were:

  2000 March 10.015 UT, 2 * 600 s R-band, seeing 0.9" - 1.2" 
  2000 March 23.019 UT, 3 * 600 s R-band, seeing 1.1" - 1.6"
  

  The two exposure sets were compared, using image blinking. The closeness of Betelgeuse implies scattered light across the error box, and hence a non-uniform limiting magnitude. Using the standard stars provided by Henden et al. (GCN #608) we estimate that most of the error box has been searched to magnitude R ~22.0.
  No candidate counterpart was found.
  We acknowledge the assistance of the La Silla staff.
  Observations were carried out at the European Southern Observatory under programme 64.H-0573(A).