HETE Burst U10893

Burst U10893 summary

  • Trigger time is
    • UTC=20030226_034631
    • GRB=GRB030226+13591
  • Triggering instrument was Fregate
  • Trigger timescale was 5.0 seconds
  • Trigger detected in 30-400 keV band


Long GRB, untriggered because detected in Ecuador Anomaly

GRB030226 (HETE U10893)

The burst GRB030226 was detected on board HETE; however, the on-board Trigger Monitor process had been instructed to reject triggers in the region of the South Atlantic Anomaly and the Ecuador Anomaly. As a result, the burst was only detected by ground processes which routinely look through the downlinked data for untriggered bursts.

The burst was localized in the WXM, with an initial error radius of 15 arcminutes (90%); subsequent analyses have moved the WXM position and reduced its radius to 6.5 arcminutes (90%). The burst was localized in the SXC, as the cross-correlation brightest peak within 2 degrees of the WXM error region was actually within the WXM error region (the ``vernier'' method). The resulting error region measured 2 arcminutes in radius (90%).

The OT discovered by Fox et al (GCN 1879) was 0.9 arcminutes from the center of the SXC error box.

Skymap of U10893 (GRB030226)

The skymap shows the published localizations by the WXM and SXC and the OT found by Fox (GCN 1879).

The GRB lightcurves in four energy bands.

Note the background variations over Ecuador (t < -100) and the SAA (t > 200). The burst trigger was invalidated on board because of the proximity to SAA.