GR-AMRVAC code applications: accretion onto compact objects, boson stars versus black holes
GR-AMRVAC code applications: accretion onto compact objects, boson stars versus black holes
复制标题
DOI：
10.1088/0264-9381/33/15/155010
复制
发表时间：
2016-07
影响因子：
3.5
通讯作者：
Z. Meliani;P. Grandclément;F. Casse;F. Vincent;O. Straub;F. Dauvergne
中科院分区：
文献类型：
--
作者：
Z. Meliani;P. Grandclément;F. Casse;F. Vincent;O. Straub;F. Dauvergne
在致密物体附近，强引力会将其特征印在物质上。包含至少一个紧凑物体的系统被观察到表现出极端的物理特性，并且通常发射高能辐射。产生最强引力场的致密天体的性质至今尚未确定。对黑洞、中子星和其他致密天体（如玻色子星）周围流体动力学的广义相对论数值模拟可能会对这个基本问题提供宝贵的见解。为了研究任意致密物体在强引力作用下的流体行为，我们发展了一个新的广义相对论流体力学程序。为此，我们将现有的通用自适应网格细化代码MPI-AMRVAC扩展到广义相对论流体力学框架，并使其适应于使用数值给定的时空度量。在这篇文章中，我们研究吸积流附近的各种类型的BS的数值度量计算的KADATH谱求解器库。我们设计了具体的测试，以检查任何代码的可靠性，打算研究BS和比较的解决方案与史瓦西黑洞的背景下获得的。我们首次利用BS对气体吸积进行了广义相对论流体动力学模拟。物质在离BS中心很小距离处的行为与黑洞的情况明显不同。特别是，我们表明，在邦迪球形吸积的背景下，到非旋转BS的质量吸积率保持不变，而它增加了史瓦西黑洞。我们还解决的情况下，非球形吸积到BS和表明，这可能会引发质量喷射从内部的BS。这一引人注目的特点打开了大门，即将调查的吸积喷射流周围的这种类型的紧凑的对象。
In the close vicinity of a compact object strong gravity imprints its signature onto matter. Systems that contain at least one compact object are observed to exhibit extreme physical properties and typically emit highly energetic radiation. The nature of the compact objects that produce the strongest gravitational fields is to date not settled. General relativistic numerical simulations of fluid dynamics around black holes, neutron stars, and other compact objects such as boson stars (BSs) may give invaluable insights into this fundamental question. In order to study the behavior of fluid in the strong gravity regime of an arbitrary compact object we develop a new general relativistic hydrodynamics code. To this end we extend the existing versatile adaptive mesh refinement code MPI-AMRVAC into a general relativistic hydrodynamics framework and adapt it for the use of numerically given spacetime metrics. In the present article we study accretion flows in the vicinity of various types of BSs whose numerical metrics are calculated by the KADATH spectral solver library. We design specific tests to check the reliability of any code intending to study BSs and compare the solutions with those obtained in the context of Schwarzschild black holes. We perform the first ever general relativistic hydrodynamical simulations of gas accretion by a BS. The behavior of matter at small distances from the center of a BS differs notably from the black hole case. In particular we demonstrate that in the context of Bondi spherical accretion the mass accretion rate onto non-rotating BSs remains constant whereas it increases for Schwarzschild black holes. We also address the scenario of non-spherical accretion onto BSs and show that this may trigger mass ejection from the interior of the BS. This striking feature opens the door to forthcoming investigations regarding accretion-ejection flows around such types of compact objects.