Triaxially-deformed Freely-precessing Neutron Stars: Continuous electromagnetic and gravitational radiation

伽马射线暴X射线余辉中三轴进动磁星的信号特征

Signature of Triaxially Precessing Magnetars in Gamma-ray Burst X-Ray Afterglows

本文从Swift/XRT数据中识别出四个X射线余辉平台期具有规则流量变化的伽马射线暴，并用三轴自由进动磁星的磁偶极辐射模型成功拟合其光变曲线，为新生毫秒磁星早期进动提供了新证据。

轨道偏心率对紧密双星中三轴形变进动中子星连续引力波的影响

Effects of orbital eccentricity on continuous gravitational waveforms from triaxially deformed precessing neutron stars in tight binaries

本研究探讨轨道偏心率对紧密双星中三轴形变进动中子星连续引力波的影响，推广解析波形以纳入偏心率效应，发现其对动力学形成的双星不可忽略且可高精度测量，助力理解双中子星形成机制。

Precession of triaxially deformed neutron stars

A deformed neutron star (NS) will precess if the instantaneous spin axis and the angular momentum are not aligned. Such a precession can produce continuous gravitational waves (GWs) and modulate electromagnetic pulse signals of pulsars. In this contribution we extend our previous work in a more convenient parameterization. We treat NSs as rigid triaxial bodies and give analytical solutions for angular velocities and Euler angles. We summarize the general GW waveforms from freely precessing triaxial NSs and use Taylor expansions to obtain waveforms with a small wobble angle. For pulsar signals,…

Precession of magnetars: dynamical evolutions and modulations on polarized electromagnetic waves

Magnetars are conjectured to be highly magnetized neutron stars (NSs). Strong internal magnetic field and elasticity in the crust may deform the stars and lead to free precession. We study the precession dynamics of triaxially-deformed NSs incorporating the near-field and the far-field electromagnetic torques. We obtain timing residuals for different NS geometries and torques. We also investigate the polarized X-ray and radio signals from precessing magnetars. The modulations on the Stokes parameters are obtained for thermal X-rays emitted from the surface of magnetars. For radio signals, we a…

Determination of mass of an isolated neutron star using continuous gravitational waves with two frequency modes: an effect of a misalignment angle

A rapidly spinning neutron star (NS) would emit a continuous gravitational wave (GW) detectable by the advanced LIGO, advanced Virgo, KAGRA and proposed third generation detectors such as the Einstein Telescope (ET). Such a GW does not propagate freely, but is affected by the Coulomb-type gravitational field of the NS itself. This effect appears as a phase shift in the GW depending on the NS mass. We have shown that mass of an isolated NS can, in principle, be determined if we could detect the continuous GW with two or more frequency modes. Indeed, our Monte Carlo simulations have demonstrated…

Precessing flaring magnetar as a source of repeating FRB 180916.J0158+65

Recently, CHIME detected periodicity in the bursting rate of the repeating FRB 180916.J0158+65. In a popular class of models, the fast radio bursts (FRBs) are created by giant magnetic flares of a hyper-active magnetar driven by fast ambipolar diffusion in the core. We point out that in this scenario the magnetar is expected to precess freely with a period of hours to weeks. The internal magnetic field $B\sim 10^{16}$G deforms the star, and magnetic flares induce sudden changes in magnetic stresses. The resulting torques and displacements of the principal axes of inertia are capable of pumping…