general relativistic astrophysics - Multi-messengaer astrophysics of gravitational wave sources

LIGO/Virgo对致密天体发出的引力波(GW)的直接探测不仅证实了广义相对论的一个关键预测，而且为研究与GW源相关的极端环境中的物理和天体物理开辟了新的机会。由于中子星合并而产生的GW170817电磁对应物的发现，坚定地确立了时间域多信使天文学的可行性和重要性。GW源是非均匀类别的物体，GW的频率/波长由发射器的线性尺寸决定。因此，产生多信使信号的相关物理过程在不同系统之间会有很大的不同，这打破了广义相对论模型中标度的简并性。例如，一颗中子星在合并之前如何与另一颗中子星相互作用，以及在合并过程之后，产生的黑洞将如何与富含中子的残骸相互作用？当两颗中子星融合成一个黑洞时，富含中子的物质的物理条件是什么？当一颗中子星在螺旋过程中变成一个大质量黑洞时，这个过程产生的电磁辐射是如何改变的？中子星的轨道动力学将如何受到强引力相互作用以及自旋-自旋和自旋-曲率相互作用的影响？学生将从所提到的纸巾中选择一到两张相关的纸巾。目标是开发一个理论框架来模拟多信使签名，并做出可被当前和未来的工具检验的预测。这是一个现象学和理论项目，重点是引力波研究的天体物理方面。

The direct LIGO/VIRGO detection of gravitational waves (GW) emitted by compact astrophysical objects not only confirmed a key prediction of general relativity but also opens up new opportunities for the investigation of physics and astrophysical in the extreme environments associated with the GW sources. The discovery of the electromagnetic counterpart of GW170817, which was due to a neutron-stars merger firmly established the viability and the importance of time-domain multi-messenger astronomy. GW sources are inhomogeneous classes of objects, and the frequencies/wavelengths of the GW are determined by the linear size of the emitter. As such, the associated physics processes that give rise to the multi-messenger signals would vary substantially among the systems which break the degeneracy of scaling in generalrelativity models. For instance, how does a neutron star interact with another neutron star before they undergo merging and how would the resulting black hole interact with the neutron-rich remnant debris after the merging process? What is the physical condition of the neutron-rich matter when two neutron stars are being fused into forming a black hole? How does the electromagnetic radiation that the process generatedis modified when a neutron star is in an in-spiral process into a massive black hole? How would the orbital dynamic of the neutron star be affected by the strong gravitational interaction and the spin-spin and spin-curvature interactions? The student will select one or two related tissues among those mentioned. The objectives are to develop a theoretical framework to model the multi-messenger signatures and to makepredictions that can be tested by current and future instruments. It is phenomenological and theoretical project, emphasis on the astrophysical aspects of gravitational wave research.