标题： GRB050709的余辉和短硬伽马暴的性质 显示英文标题

标题： The afterglow of GRB050709 and the nature of the short-hard gamma-ray bursts

摘要： 长期存在的伽马射线暴（GRB）谜团的最后一章集中在短而硬的伽马射线暴类别的起源上，从理论上怀疑它们是由中子星或黑洞双星系统的合并产生的。 由于1997年发现长时标GRB的宽带（X射线、光学和射电）余辉辐射后我们对长时标GRB理解的革命性进展，许多针对短而硬的伽马射线暴余辉的搜索已经被进行了。 在这里，我们报告了短而硬的伽马射线暴的X射线余辉的发现，其精确位置使我们可以明确地将其与红移z=0.160处的一个恒星形成星系联系起来，并且其光学光变曲线明确排除了超新星关联的可能性。 结合来自另外三个近期短而硬的伽马射线暴的结果，这表明短而硬的伽马射线暴释放的能量远低于长时标GRB。 需要年轻恒星群体的模型，例如磁星和 collapsar 被排除在外，而合并的简并双星仍然是最有希望的前身候选者。 显示英文摘要

摘要： The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class, suspected on theoretical grounds to result from the coalescence of neutron star or black hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical, and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst whose accurate position allows us to unambiguously associate it with a star-forming galaxy at redshift z=0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates.