Tidal disruptions of white dwarfs as probes for intermediate mass black holes in globular clusters

有证据表明，中等质量黑洞（IMBHs）存在于某些球状星团中。当恒星在星团中扩散时，一些恒星将不可避免地离黑洞足够近，以至于它们遭受潮汐破坏。IMBH假说的一个吸引人的特点是它不仅有可能破坏太阳型恒星，也有可能破坏致密的白色矮星。我们最近研究了白色矮星的命运，这些矮星靠近黑洞，足以被破坏和压缩到引发爆炸性核燃烧的程度。我们发现热核点火是所有质量的白色矮星在潮汐半径内通过的自然结果。一个特殊的，不发光的热核爆炸伴随着软X射线瞬态信号，如果被探测到，将是一个令人信服的证据，为IMBH的存在。在这个提议中，我们建议在一个固定的黑洞背景度规上用相对论方法探索破裂过程。具体目标是将相对论重力和流体力学应用到当前的流体力学加核网络模型中。使用这个工具，我们将研究特别接近的遭遇，其中强引力效应是重要的，无论是旋转和非旋转黑洞。

Suggestive evidence has accumulated that intermediate mass black holes (IMBHs) exist in some globular clusters. As stars diffuse in the cluster, some will inevitably wander sufficiently close to the hole that they suffer a tidal disruption. An attractive feature of the IMBH hypothesis is its potential to disrupt not only solar-type stars but also compact white dwarf stars. We have recently investigated the fate of white dwarfs that approach the hole close enough to be disrupted and compressed to such an extent that explosive nuclear burning is triggered. We found that thermonuclear ignition is a natural outcome for white dwarfs of all masses passing well within the tidal radius. A peculiar, underluminous thermonuclear explosion accompanied by a soft X-ray transient signal would, if detected, be a compelling testimony for the presence of an IMBH.These previous calculations were based on the use of a relativistic pseudo-potential. In this proposal we suggest to explore the disruption process in a relativistic approach on a fixed black hole background metric. The specific goal is to implement relativistic gravity and hydrodynamics into the current hydrodynamics plus nuclear network model. Using this tool we will study particularly close encounters where strong gravity effects are important, both with rotating and non-rotating black holes.