Isolated pulsars are rotating neutron stars with accurately measured angular velocities $Ω$, and their time derivatives which show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of debate in detail, the commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. Other processes, including the emission of gravitational radiation, and of relativistic particles (pulsar wind), are also being considered. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of $Ω$. This relation leads to the power law $\dotΩ$ = -K $Ω^{\rm n}$ where $n$ is called the braking index. The MDR model predicts $n$ exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of $n$, individually accurate to a few percent or better, in the range 1$ <$ n $ < $ 2.8, which is consistently less than the predictions of the MDR model. In spite of an extensive investigation of various modifications of the MDR model, no satisfactory explanation of observation has been found as yet.
We employ four physically realistic equations of state, and two computational codes, to model the dynamical effects of rotation on the braking index in the MDR model. In addition to this we simulate an effect on moment of inertia where we assume a certain amount of superfluid matter has manifest between the crust and core region of the star thus essentially eliminating momentum transfer between the two regions. We find that the effects of rotation on braking index are significant at high frequencies, but have little effect at frequencies consistent with the most accurately measured pulsars to-date.
Faraday Conversion and Rotation In Uniformly Magnetized Relativistic Plasmas
给出了均匀磁化相对论等离子体中法拉第转换系数和旋转系数的精确拟合公式。该公式可直接应用于旋转测量和圆极化（CP）生产的喷流和热吸积流。我们展示了任意各向同性粒子分布的配方和结果，特别是热和幂律。精确的法拉第转换系数被发现随着粒子能量的增加接近零。法拉第转换系数和旋光系数的非线性校正是保证Sgr A ~* CP解释可靠性的必要条件。
X-ray emission from magnetized neutron star atmospheres at low mass accretion rates. I. Phase-averaged spectrum
最近在低光度下对X射线天体的观测首次将高磁化中子星大气在低质量吸积率下的发射理论模型（$\dot{M} \lesssim 10^{15}$ g s $^{-1}$）与宽带X射线数据进行了比较。本文的目的是研究中子星大气中低$\dot{M}$的光谱形成，并对发射区的物理性质进行参数研究。我们得到的静态大气的结构，假设库仑碰撞是占主导地位的减速过程。大气的上部被制动等离子体强烈加热，达到30-40 keV的温度，而其密度更大的等温内部则要冷得多（~2 keV）。我们数值求解了磁康普顿散射、自由-自由过程和电子碰撞激发引起的非热回旋辐射的大气中的偏振辐射转移。在低光度X射线谱仪中观察到的强偏振发射光谱具有双峰形状。低能量的“热”成分主要是非常光子，由于它们在软能量下的平均自由程很长，它们可以从更深的层离开大气。我们发现，即使在没有碰撞激发的情况下，在加热的非等温部分的大气中，由于共振康普顿化，也会形成一个高能量的成分。然而，后者影响两种组分的比例。强回旋加速线起源于光学薄的最上部区域。模型与GX 304-1的NuSTAR和Swift/XRT观测的拟合提供了具有合理参数的数据的准确描述。因此，该模型可以再现在低光度X射线谱仪中观察到的特征双峰谱，并提供了对谱形成的见解。
Effect of a Weak Electromagnetic Field on Particle Acceleration by a Rotating Black Hole
研究了旋转黑洞周围电磁场中视界附近的高能带电粒子碰撞，揭示了获得任意大质心能量的微调条件.我们证明了当一个带电粒子从最内层稳定圆轨道（ISCO）坠落并在视界附近与另一个粒子碰撞时，当均匀磁化旋转的黑洞任意接近最大旋转时，CM能量可以任意大.最近，Frolov [Phys. Rev. D 85，024020（2012）]提出，如果磁场任意强，当粒子与在均匀磁化的史瓦西黑洞的视界附近以有限能量绕ISCO轨道运行的带电粒子碰撞时，CM能量可以任意高。我们表明，带电粒子轨道ISCO周围的旋转黑洞需要任意高的能量在强场限制。这表明弗罗洛夫的过程对黑洞的旋转是不稳定的。尽管如此，我们看到磁场可能会大大提高旋转黑洞在天体物理学情况下作为粒子加速器的能力。
Magnetically supramassive and hypermassive compact stars
University of the Ryukyus（琉球大学）；Tohoku University（东北大学）；Observatoire de Paris, Universite PSL, CNRS, Sorbonne Universite（巴黎天文台，巴黎文理研究大学，法国国家科学研究中心，索邦大学）；Laboratoire de Mathématiques de Bretagne Atlantique, CNRS UMR 6205, Université de Bretagne Occidentale（布列塔尼大西洋数学实验室，法国国家科学研究中心 UMR 6205，布列塔尼西部大学）；Stony Brook University（石溪大学）；National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校超级计算应用国家中心）；Tokyo University of Technology（东京工业大学）；University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；Academy of Athens（雅典科学院）
