论文标题
使用事件地平线望远镜探测射手座A*的阴影图像
Probing the Shadow Image of the Sagittarius A* with Event Horizon Telescope
论文作者
论文摘要
在各种频率上对乳白色银河中心的最新观察表明，超级紧凑的物体。通常，假定那个超大型物体是一个“黑洞”，具有超过400万个太阳能物质。在这项工作中，我们将观察性外观研究为$ 230 $ ghz，并探究了射手座-a*（sgr a*）的性质。在这里，我们考虑了第一种Joshi-Malafarina-Narayan（JMN-1）和Janis-Newman-Winicour（JNW）Naked Singularity SpaceTime，它们是爱因斯坦田间方程的各向异性流体溶液。通过辐射效率低下的积聚流（RIAF），我们使用分析模型进行发射和吸收系数来求解一般的相对论辐射转移方程。然后，将所得的发射用于生成图像，以预测来自当前和未来事件地平线望远镜（EHT）阵列的合成非常长的基线干涉仪（VLBI）图像的SGR A*的性质。三种不同的EHT阵列配置被用于模拟裸奇异点和黑洞的模型。这可能对基线几乎没有影响，但会增加U-V平面网格，这使得捕获一个更好的分辨图像使其可行。因此，对于即将到来的SGR A*的阴影图像非常有趣且有用，以预测它是超大型黑洞还是裸露的奇异性。
Recent observations of the Milky-way galactic center at various frequencies suggest a supermassive compact object. Generally, that supermassive compact object is assumed to be a `Black Hole', having more than four million solar masses. In this work, we study the observational appearance at $230$ GHz and probe the nature of Sagittarius-A* (Sgr A*) as the naked singularity. Here, we consider the first type of Joshi-Malafarina-Narayan (JMN-1) and Janis-Newman-Winicour (JNW) naked singularity spacetimes which are anisotropic fluid solutions of the Einstein field equations. Motivated by radiatively inefficient accretion flows (RIAF), we use an analytical model for emission and absorption coefficients to solve the general relativistic radiative transfer equation. The resulting emission is then utilized to generate images to predict the nature of the Sgr A* with synthetic Very Long Baseline Interferometry (VLBI) images from current and future Event Horizon Telescope (EHT) arrays. Three different EHT array configurations are being used to simulate the models of naked singularities and a black hole. This may have little effect on the baseline, but it would increase the u-v plane gridding, making it feasible to capture a better-resolved image. Therefore, it is quite interesting and useful for the upcoming shadow image of the Sgr A* to predict whether it is a supermassive black hole or a naked singularity.
