The afterglow and elliptical host galaxy of the short gamma-ray burst GRB 050724.
The afterglow and elliptical host galaxy of the short gamma-ray burst GRB 050724.
复制标题
短伽马射线暴 GRB 050724 的余辉和椭圆主星系。
作者：
E. Berger;P. Price;S. Cenko;A. Gal;A. Soderberg;M. Kasliwal;D. Leonard;P. B. Cameron;D. Frail;S. Kulkarni;D. Murphy;W. Krzemiński;T. Piran;B. Lee;K. Roth;D. moon;D. Fox;F. Harrison;S. E. Persson;B. Schmidt;B. Penprase;J. Rich;B. Peterson;L. Cowie
尽管有丰富的现象学，但伽马射线暴(GRB)根据持续时间和光谱硬度被分为两类--长软暴和短硬暴。长伽玛暴余辉发射的发现是一个分水岭事件，确定了它们的起源是恒星形成的星系，因此是大质量恒星的死亡，并表明能量释放约10(51)erg。虽然理论论证表明，短伽玛暴是在双星致密天体(中子星或黑洞)的聚合中产生的，但这些事件的前身、能量和环境仍然难以捉摸，尽管最近进行了定位。在这里，我们报告了从短爆发伽马射线暴050724中发现的第一个射电余辉，它明确地将其与红移为z=0.257的椭圆星系联系在一起。我们发现，这次爆发的能量来源与长伽玛暴的相对论火球机制相同，喷出物可能在喷流中准直，但总能量释放要小10-1000倍。更重要的是，宿主星系的性质表明，短伽玛暴起源于古老的恒星群(>；1 Gyr；)，这强化了早先的说法，并为凝聚致密天体双星作为前身提供了支持。
Despite a rich phenomenology, gamma-ray bursts (GRBs) are divided into two classes based on their duration and spectral hardness--the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing their origin to star-forming galaxies, and hence the death of massive stars, and indicating an energy release of about 10(51) erg. While theoretical arguments suggest that short GRBs are produced in the coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10-1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors.