论文标题
来自GRMHD模拟的SGR A*辐射模型的参数调查，并具有自一致的电子加热
A parameter survey of Sgr A* radiative models from GRMHD simulations with self-consistent electron heating
论文作者
论文摘要
银河中心黑洞候选SGR A*是研究低亮度积聚物理学的最佳目标，包括具有近红外和亚毫米的波长长基线干涉测量学实验。在这里，我们将一般相对论MHD模拟参数调查产生的图像和光谱与SGR A*的近红外观察结果相比。我们的模型跨越了弱磁化强度的限制，并使用一系列的亚网格处方进行电子加热。我们发现两类的场景可以解释亚毫米光谱峰的宽阔形状和高度可变的近红外耀斑发射。弱磁化的“磁盘喷射”模型，其中大多数发射是在喷气壁附近产生的，与过去的工作一致，以及强烈的磁化（磁性捕集的磁盘）模型，在这些模型中都存在热电子。由于法拉第旋转强，磁盘喷射模型在亚毫升波长下被强烈去极化，这与SGR A*的观察结果不一致。相反，我们偏爱强磁化模型，该模型可以很好地描述中位数和高度可变的线性极化信号。相同的模型还可以解释观察到的平均法拉第旋转度量，并可能在SGR A*近红外耀斑中看到的极化信号。
The Galactic center black hole candidate Sgr A* is the best target for studies of low-luminosity accretion physics, including with near-infrared and submillimeter wavelength long baseline interferometry experiments. Here we compare images and spectra generated from a parameter survey of general relativistic MHD simulations to a set of radio to near-infrared observations of Sgr A*. Our models span the limits of weak and strong magnetization and use a range of sub-grid prescriptions for electron heating. We find two classes of scenarios can explain the broad shape of the submillimeter spectral peak and the highly variable near-infrared flaring emission. Weakly magnetized "disk-jet" models where most of the emission is produced near the jet wall, consistent with past work, as well as strongly magnetized (magnetically arrested disk) models where hot electrons are present everywhere. Disk-jet models are strongly depolarized at submillimeter wavelengths as a result of strong Faraday rotation, inconsistent with observations of Sgr A*. We instead favor the strongly magnetized models, which provide a good description of the median and highly variable linear polarization signal. The same models can also explain the observed mean Faraday rotation measure and potentially the polarization signals seen recently in Sgr A* near-infrared flares.
