Electromagnetic transients from radioactive decays accompanying short gamma-ray bursts

两颗中子星或一颗中子星和一个恒星质量的黑洞的最终激发阶段和随后的合并是千赫兹区域内的主要引力波来源。此外，它们被认为是(短暂的)伽马射线爆发现象背后的“中心引擎”。在合并过程中，引力力矩将解压的中子星物质发射到未受束缚或几乎未受束缚的偏心轨道。这种碎片由放射性原子核组成，最终衰变成所谓的r过程元素，这种衰变必须产生各向同性、明亮但迅速衰变的电磁瞬变。确定这种瞬变现象至关重要，因为它提高了地面引力波探测器设施的有效灵敏度，并通过提供关于宿主星系、当地环境以及双星性质和演化的信息，在天体物理背景下进行了密集的双星合并。因此，目前和未来的瞬变探测可以限制宇宙中最重元素的来源仍然未知。这项提议的目的是克服后一种限制，并从碎片材料演化的最初合并过程(包括从核能释放到流体动力学的反馈)到最后的光曲线进行完整的计算。

The final inspiral stages and the subsequent coalescence of two neutron stars or of a neutron star and a stellar-mass black hole are the prime gravitational wave sources in the kilohertz regime. Moreover, they are thought to be the "central engines" behind the (short) Gamma-ray burst phenomenon. During the merging process, gravitational torques launch decompressed neutron star matter into unbound or nearly unbound, eccentric orbits. This debris consists of radioactive nuclei that finally decay into so-called r-process ("rapid neutron capture") elements and this decay must produce an isotropic, bright, but rapidly decaying electromagnetic transient. The identification of such transients is crucial since it increases the effective sensitivity of ground-based gravitational wave detector facilities and it places compact binary mergers in an astrophysical context by providing information on the host galaxy, the local environment and on binary star properties and evolution. Thus, current and future transient surveys can constrain the still unknown origin of the heaviest elements in the Universe. The aim of this proposal is to overcome the latter restriction and to perform a complete calculation from the initial merger process over the evolution of the debris material (including feedback from nuclear energy release onto the hydrodynamics) to the final light curves.