论文标题
被磁场屏蔽的黑洞
Black holes shielded by magnetic fields
论文作者
论文摘要
黑洞（BHS）是通过倒塌和/或合并磁化祖细胞形成的，具有穿透事件范围的磁场，并且有几种可能的情况。因此，假定外部培养基是真空的无毛定理，在这种情况下不适用。考虑到这一点，并考虑了沉浸在均匀磁场$ b $中的质量$ m $的Schwarzschild Bh，我们表明，与测试粒子的赤道圆形轨道相关的所有三个频率对于Radii $ r_b> 2b> 2B^{ - 1} $的轨道来说都是虚构的。它表明，如果BH被$ b \ sim r_g^{ - 1} $的磁场包围（其中$ r_g $是BH的重力半径），一个测试粒子无法继续从/$ r> r_b $中的常规测量运动继续进行，因此，积分盘可能无法构成其他一体的运动。由于通常通过观察其对附近的恒星和气体的影响来检测到BHS，因此$ b \ sim r_g^{ - 1} $的磁场可以以一种无法检测到的方式屏蔽BH。我们以这种理论研究的态度进行了动机，并考虑了天体物理BH周围（半径$ r_f $）的球体（radius $ r_f $），我们限制了$ b $，在此上面，磁性化的BH可能仍然无法检测到。例如，$ m = 10^9m _ {\ odot} $ bh被$ b> 10^6 $ g包围，$ m = 100m _ {\ odot} $ bh被$ b> 10^{14} $ g包围，可以保持不可检测，对于$ r_f \ sim 10^5r_g $。换句话说，我们的结果还解释了为什么检测到的SMBH出奇的磁场弱磁场。
Black holes (BHs) formed by collapsing and/or merging of magnetized progenitors, have magnetic fields penetrating the event horizon, and there are several possible scenarios. Thus, the no-hair theorem that assumes the outside medium is a vacuum, is not applicable in this case. Bearing this in mind and considering a Schwarzschild BH of mass $M$ immersed in a uniform magnetic field $B$, we show that all three frequencies related to the equatorial circular orbit of a test particle become imaginary for the orbits of radii $r_B > 2B^{-1}$. It signifies that if a BH is surrounded by a magnetic field of order $B \sim R_g^{-1}$ (where $R_g$ is the gravitational radius of the BH), a test particle could unable to continue its regular geodesic motion from/at $r > r_B$, hence the accretion disk could not be formed, and the motion of other stellar objects around the BH could be absent. As the BHs are generally detected by watching for their effects on nearby stars and gas, a magnetic field of order $B \sim R_g^{-1}$ could be able to shield a BH in such a way that it could remain undetectable. Motivated with this theoretical investigation and considering the sphere (of radius $r_f$) of magnetic influence around an astrophysical BH, we constrain $B$, above which a magnetized BH could remain undetectable. For example, $M=10^9M_{\odot}$ BH surrounded by $B > 10^6$ G and $M=10M_{\odot}$ BH surrounded by $B > 10^{14}$ G could remain undetectable for $r_f \sim 10^5R_g$. In other words, our result also explains why a detected SMBH has surprisingly weak magnetic field.
