Gamma-ray Burst 010326

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN notice #1014
  G. Ricker, D. Lamb, and S. Woosley on behalf of the HETE Science Team;
  R. Vanderspek, G. Crew, J. Doty, G. Monnelly, J. Villasenor; N. Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, G. Pizzichini, and G. Prigozhin, on behalf of the HETE Operations and HETE Optical-SXC Teams;
  N. Kawai, M. Matsuoka, Y. Shirasaki, T. Tamagawa, A. Yoshida, E. Fenimore, M. Galassi, B. Preger, and C. Graziani, on behalf of the HETE WXM Team;
  J-L Atteia, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE FREGATE Team; write:
  On 26 March 2001 at 03:15:00 UTC, a hard spectrum, high energy transient at high galactic latitude was detected and localized by HETE. Both the FREGATE and the WXM instruments detected the event. The burst triggered FREGATE in the 30-400 keV band.
  The preliminary coordinates of the burst are R.A. = 11h50m59.11s, Dec. = -23032'44" (J2000), derived from combining data from the WXM and Boresighted Optical Cameras. The statistical error radius in the WXM localization is 10 arcmin (90% confidence). In addition, we estimate a systematic error radius at present of 20 arcmin about this location. The spacecraft aspect was known to an accuracy of +/- 2 arcmin (95% confidence) from the optical cameras, and will be improved.
  The burst exhibited a multiple-peaked structure and lasted about 25 seconds. The peak flux seen with FREGATE (6-30 keV) was ~1 Crab. The peak flux was significantly less in the WXM.
  Follow-up observations of this GRB event are encouraged.
  Additional information on GRB010326 (including light curves and the WXM error box), as well as the HETE mission, is available at: http://space.mit.edu/HETE/

  Acronyms:
  HETE=High Energy Transient Explorer
  FREGATE=French Gamma Ray Telescope
  WXM=Wide Field X-ray Monitor
  SXC=Soft X-ray Camera
  

  

• GCN notice #1015
  G. Ricker, D. Lamb, and S. Woosley on behalf of the HETE Science Team;
  R. Vanderspek, G. Crew, J. Doty, G. Monnelly, J. Villasenor; N. Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, G. Pizzichini, and G. Prigozhin, on behalf of the HETE Operations and HETE Optical-SXC Teams;
  N. Kawai, M. Matsuoka, Y. Shirasaki, T. Tamagawa, A. Yoshida, E. Fenimore, M. Galassi, B. Preger, and C. Graziani, on behalf of the HETE WXM Team;
  J-L Atteia, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE FREGATE Team; write:
  The systematic error radius for the HETE localization of GRB010326 by the WXM has been refined to 10 arcminutes. Further refinement is expected.
  Follow-up observations of this GRB event are encouraged.
  Additional information on GRB010326, as well as for the HETE mission, is available at:
  http://space.mit.edu/HETE/ Acronyms: HETE=High Energy Transient Explorer FREGATE=French Gamma Ray Telescope WXM=Wide Field X-ray Monitor SXC=Soft X-ray Camera
• GCN notice #1016
  Howard E. Bond, Space Telescope Science Institute reports:
  I have obtained CCD images centered on the position of GRB 010326, 11:50:59.1 -23:32:44 (J2000), with the Cerro Tololo Interamerican Observatory 0.9-m reflector, on 2001 March 26 from 08:18 to 08:50 UT. A Johnson V filter was used, for a total of 1800 sec of integration, with a field of view of 13' x 13'.
  A preliminary comparison of the CCD frames with the 2nd-generation red Digitized Sky Survey images of the same field discloses no obvious new objects.
• GCN notice #1017
  P.A. Price, T.S. Axelrod, B.P. Schmidt (RSAA, ANU), D.E. Reichart, J.S. Bloom and D. Fox (Caltech) report on behalf of a larger international GRB collaboration:
  We have observed the error-circle of the HETE-2 GRB 010324 with the robotic 50-inch telescope at Mount Stromlo Observatory starting at 2001 Mar 26.45 UT (7.5 hours after the GRB). Our 5x300 sec images cover the entire error box, and go fainter than the DSS-2 red plates. From a preliminary visual comparison of our images with the DSS-2 plates, we do not detect any obvious bright optical counterpart.
  Further observations are planned.
• GCN notice #1022
  P.A. Price, T.S. Axelrod, B.P. Schmidt (RSAA, ANU) and D.E. Reichart (Caltech) report on behalf of a larger international GRB collaboration:
  "We have re-observed the entire error-circle of GRB 010326A with a further 5x300 sec exposures with the robotic 50-inch telescope at Mount Stromlo Observatory commencing at Mar 26.64 (12 hours after the GRB). Visual inspection of the residual images after subtraction with the previous epoch with ISIS does not reveal any variable sources that are not present on the DSS-2. We estimate that the limiting magnitude of our images is R ~ 21.5 mag, on comparison with common stars in the USNO catalogue."
  This message may be cited.
• GCN notice #1026
  A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
  We have acquired preliminary BVRcIc all-sky photometry for an 11x11 arcmin field centered at the HETE localization for GRB010326 (GCN 1015) with the USNOFS 1.0-m telescope on one marginally photometric night with poor seeing. 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/grb010326a.dat The current photometry has a potential external zero-point error of about three 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. Further calibration of this field will not be performed unless an optical counterpart is discovered.
• GCN notice #1030
  K. Hurley, on behalf of the Ulysses GRB and HETE teams; T. Cline, on behalf of the Ulysses, Konus-Wind, and HETE GRB teams; E. Mazets and S. Golenetskii, on behalf of the Konus-Wind and Konus-A GRB teams; and G. Ricker, D. Lamb, C. Graziani, E. Fenimore, N. Kawai, and J.-L. Atteia, on behalf of the HETE team report:
  Ulysses, Konus-Wind and Konus-A observed GRB010326A. This burst had a duration of ~25 s, a 17 keV - 2.5 MeV fluence of ~4x10^-5 erg/cm2, and a peak flux over 0.25 s of ~8x10^-6 erg/cm2 s. From a cross-correlation of the Ulysses and Konus-Wind time histories, we have triangulated the location of the burst to an annulus centered at RA(2000)=178.727 deg., Decl(2000)=30.803 deg., and radius 81.702+/- 0.028 deg. (3 sigma confidence). The triangulation based on the Konus-Wind and the Konus-A data resulted in an annulus centered at RA(2000)=94.662 deg., Decl(2000)=21.978 deg., and radius 69.7+/- 0.4 deg. (1 sigma confidence). Combining these data, we are able to restrict the location of the burst to the following ~180 square arcmin. error box.

    RA(2000)       DEC(2000)
  132.9630 o     -38.3005 o (CENTER)
  132.3408 o     -38.5784 o (CORNER)
  132.3988 o     -38.5441 o (CORNER)
  131.5271 o     -38.0568 o (CORNER)
  131.5851 o     -38.0230 o (CORNER)
  

  This location is consistent with the spectra and time history seen in the four HETE FREGATE detectors. The above error box can be refined by further processing.
  On this basis, we have concluded that the WXM location reported in GCN 1014 for this burst is spurious. This burst is distinct from the other GRBs (GRB010326B, GCN 1018; GRB010213, GCN 934) for which HETE WXM locations have been reported, in that it has a very low signal-to-noise excess count rate in the WXM, and our further analysis suggests that it is this fact that accounts for the spurious location. The HETE team apologizes for any inconvenience arising from the spurious location.
• GCN notice #1040
  S.B.Pandey, C.S. Stalin and V. Mohan (UPSO, Nainital) report :
  "We have observed the central 13' X 13' field of GRB 010326b (GCN 1018) on 26th and 31st March 2001 in R band using the CCD attached to the 104-cm Sampurnanand telescope of the State Observatory Nainital. On March 26th four exposures and on 31st March three exposures of 1200s each were taken. On comparing these frames we don't find any new fading object down to a limiting magnitude of R ~ 21.0.
  This message may be cited."