Scientific Highlights of the HETE-2 Mission

摘要

The HETE-2 mission has been highly productive. It has observed more than 250GRBs so far. It is currently localizing 25 - 30 GRBs per year, and haslocalized 43 GRBs to date. Twenty-one of these localizations have led to thedetection of X-ray, optical, or radio afterglows, and as of now, 11 of thebursts with afterglows have known redshifts. HETE-2 has confirmed theconnection between GRBs and Type Ic supernovae, a singular achievement andcertainly one of the scientific highlights of the mission so far. It hasprovided evidence that the isotropic-equivalent energies and luminosities ofGRBs are correlated with redshift, implying that GRBs and their progenitorsevolve strongly with redshift. Both of these results have profound implicationsfor the nature of GRB progenitors and for the use of GRBs as a probe ofcosmology and the early universe. HETE-2 has placed severe constraints on anyX-ray or optical afterglow of a short GRB. It is also solving the mystery of"optically dark' GRBs, and revealing the nature of X-ray flashes.