论文标题
潮汐破坏事件和准周期爆发中的磁统治磁盘
Magnetically Dominated Disks in Tidal Disruption Events and Quasi-Periodic Eruptions
论文作者
论文摘要
经典的辐射压力不稳定性一直是稀薄，辐射有效的积聚磁盘的持续理论特征，其增生速率为1-100％。但是，只有有限的证据表明其在自然界中的发生：一些X射线二进制文件的快速心跳振荡，现在，也许是新的每小时X射线瞬变，称为Quasi-Periodic喷发（QPES）。已经观察到在潮汐破坏事件（TDE）中形成的积聚磁盘和平侵入不稳定的增生率的范围，而没有表现出任何明显的不稳定迹象。我们试图通过构建细磁积聚磁盘的稳态1D模型来解释这些系统中这种不稳定的发生。假定磁盘中的局部磁压由由磁反转不稳定（MRI）产生的发电机引起的环形场所支配。我们选择了通过最近的磁流体动力模拟验证的MRI饱和度的物理动机标准，以确定磁盘中磁性压力的强度。 The resulting magnetic pressure support efficiently shrinks: (1) the parameter space of unstable mass accretion rates, explaining the absence of instability in systems such as TDEs and (2) the range of unstable radii in the inner accretion disk, which can shorten the quasi-periods of instability limit-cycles by more than three orders of magnitude, explaining the observed periods ( a few hrs) of QPEs.除了检查强磁盘的稳定性外，我们还预测了其他观察性特征，例如光谱硬化因子和喷射仪表，以测试我们的磁盘模型的兼容性，并观察到明显稳定的TDE磁盘。
The classical radiation pressure instability has been a persistent theoretical feature of thin, radiatively efficient accretion disks with accretion rates 1 to 100 per cent of the Eddington rate. But there is only limited evidence of its occurrence in nature: rapid heartbeat oscillations of a few X-ray binaries and now, perhaps, the new class of hourly X-ray transients called quasi-periodic eruptions (QPEs). The accretion disks formed in tidal disruption events (TDEs) have been observed to peacefully trespass through the range of unstable accretion rates without exhibiting any clear sign of the instability. We try to explain the occurrence or otherwise of this instability in these systems, by constructing steady state 1D models of thin magnetic accretion disks. The local magnetic pressure in the disk is assumed to be dominated by toroidal fields arising from a dynamo sourced by magneto-rotational instability (MRI). We choose a physically motivated criterion of MRI saturation, validated by recent magnetohydrodynamic simulations, to determine the strength of magnetic pressure in the disk. The resulting magnetic pressure support efficiently shrinks: (1) the parameter space of unstable mass accretion rates, explaining the absence of instability in systems such as TDEs and (2) the range of unstable radii in the inner accretion disk, which can shorten the quasi-periods of instability limit-cycles by more than three orders of magnitude, explaining the observed periods ( a few hrs) of QPEs. In addition to examining stability properties of strongly magnetized disks, we predict other observational signatures such as spectral hardening factors and jet luminosities to test the compatibility of our disk models with observations of apparently stable TDE disks.
