Simulating the pericentre passage of the Galactic centre star S2
Simulating the pericentre passage of the Galactic centre star S2
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模拟银河中心恒星 S2 的近心通过
DOI：
10.1051/0004-6361/201833156
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发表时间：
2018
影响因子：
6.5
通讯作者：
Ballone
中科院分区：
文献类型：
--
作者：
Schartmann;Burkert;Ballone
上下文我们对Sgr A*-银河系中心（GC）的大质量黑洞（BH）-周围吸积流密度分布的了解仅依赖于两个测量：一个在几个史瓦西半径（Rs）的距离处，另一个在大约105 Rs处，通常由幂律桥接，这是由磁流体动力学模拟支持的。这颗所谓的S2星星在2018年5月1500 Rsin左右到达了最接近大质量BH的地方。有人提出，它的恒星风与距Sgr A* 这个距离的高密度吸积流的相互作用将导致可探测的长达一个月的X射线耀斑。我们的目标是验证S2星星风是否可以作为一种诊断工具来推断在其近心点（一个未探测的距离制度）朝向Sgr A* 的吸积流的性质，把重要的限制BH吸积流models. Methods。我们运行一系列的三维自适应网格细化模拟的帮助下，RAMSES代码，其中包括现实的治疗S2的恒星风与吸积流的相互作用沿着其轨道和-除了流体动力学和philical效应-包括潮汐相互作用与大规模BH。这些是后处理，以获得可观察的2-10 keV窗口中的X射线发射。对于典型的吸积流模型，没有发现Sgr A* 的X射线发射显著过量。对于显著增加的吸积流密度，产生可测量的过量。然而，这可以排除标准的幂律吸积流模型，因为在这种情况下，没有S2风相互作用的热X射线发射已经超过了观测到的静态光度。只有风参数的显著变化（质量损失率的增加和风速的减小）才可能导致（勉强）可观测到的X射线耀斑事件。即使在S2星星的近心点通过期间探测到（长达一个月的）X射线耀斑，也不允许对Sgr A* 周围的吸积流施加严格的约束，因为依赖于多个参数（吸积流模型以及恒星风）导致的简并。
Context. Our knowledge of the density distribution of the accretion flow around Sgr A*– the massive black hole (BH) at our Galactic centre (GC) – relies on two measurements only: one at a distance of a few Schwarzschild radii (Rs) and one at roughly 105Rs, which are usually bridged by a power law, which is backed by magnetohydrodynamical simulations. The so-called S2 star reached its closest approach to the massive BH at around 1500Rsin May 2018. It has been proposed that the interaction of its stellar wind with the high-density accretion flow at this distance from Sgr A*will lead to a detectable, month-long X-ray flare.Aims. Our goal is to verify whether or not the S2 star wind can be used as a diagnostic tool to infer the properties of the accretion flow towards Sgr A*at its pericentre (an unprobed distance regime), putting important constraints on BH accretion flow models.Methods. We run a series of three-dimensional adaptive mesh refinement simulations with the help of the RAMSES code which include the realistic treatment of the interaction of S2’s stellar wind with the accretion flow along its orbit and – apart from hydrodynamical and thermodynamical effects – include the tidal interaction with the massive BH. These are post-processed to derive the X-ray emission in the observable 2–10 keV window.Results. No significant excess of X-ray emission from Sgr A*is found for typical accretion flow models. A measurable excess is produced for a significantly increased density of the accretion flow. This can, however, be ruled out for standard power-law accretion flow models as in this case the thermal X-ray emission without the S2 wind interaction would already exceed the observed quiescent luminosity. Only a significant change of the wind parameters (increased mass loss rate and decreased wind velocity) might lead to an (marginally) observable X-ray flaring event.Conclusion. Even the detection of an (month-long) X-ray flare during the pericentre passage of the S2 star would not allow for strict constraints to be put on the accretion flow around Sgr A*due to the degeneracy caused by the dependence on multiple parameters (of the accretion flow model as well as the stellar wind).
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DOI：
10.1086/312035
发表时间：
1999-03
期刊：
The Astrophysical Journal Letters
影响因子：
--
作者：
E. Quataert;R. Narayan;M. Reid
通讯作者：
E. Quataert;R. Narayan;M. Reid
DOI：
10.1088/0004-637x/750/1/58
发表时间：
2012-01
期刊：
The Astrophysical Journal
影响因子：
--
作者：
A. Burkert;M. Schartmann;C. Alig;S. Gillessen;R. Genzel;T. Fritz;F. Eisenhauer
通讯作者：
A. Burkert;M. Schartmann;C. Alig;S. Gillessen;R. Genzel;T. Fritz;F. Eisenhauer
银河系中心云 G2 紧凑源场景的流体力学模拟
DOI：
10.1088/0004-637x/776/1/13
发表时间：
2013
期刊：
The Astrophysical Journal
影响因子：
--
作者：
A. Ballone;M. Schartmann;A. Burkert;S. Gillessen;R. Genzel;T. Fritz;F. Eisenhauer;O. Pfuhl;T. Ott
通讯作者：
T. Ott
银河系中心年轻恒星盘内诞生的气云 G2 的 3D 自适应网格细化模拟
DOI：
10.1088/0004-637x/811/2/155
发表时间：
2015
期刊：
The Astrophysical Journal
影响因子：
--
作者：
M. Schartmann;A. Ballone;Andreas Burkert;S. Gillessen;R. Genzel;O. Pfuhl;F. Eisenhauer;P. Plewa;T. Ott;Elizabeth George;M. Habibi
通讯作者：
M. Habibi
SGR A的直径和固有运动
DOI：
--
发表时间：
1996
期刊：
影响因子：
--
作者：
D. Backer
通讯作者：
D. Backer