Observations of Gamma-Ray Bursts by HETE-2

The High Energy Transient Explorer 2 (HETE-2), launched in October 2000, is currently localizing gamma-ray bursts (GRBs) at a rate of ∼20 yr−1, many in real time. As of April 2003, HETE-2 had localized 39 GRBs; 16 localizations had led to the detection of an X-ray, optical, or radio afterglow. In the last four months (January–April 2003), HETE-2 had localized 8 GRBs, among which 7 had afterglows. The prompt position notification of HETE-2 enabled probing the nature of so-called “dark bursts” for which no optical afterglows were found despite of accurate localizations. In some cases, the optical afterglow was pp. 2737–2740 c ©2003 by Universal Academy Press, Inc.