A Neutron Star Atmosphere in the Laboratory With Petawatt Lasers

We discuss the preliminary estimates to create Neutron Star atmospheric conditions in the laboratory and the possibility of generating photon bubbles. The minimal requirements for photon-bubble instability could potentially be met with a properly configured 10 ps petawatt laser experiment. The high energy (multi-MeV) electrons generated by an ultra-intense laser interacting with a foil are coupled to the electrons in the solid to heat the entire solid generating high thermal temperatures. Small amounts of matter could potentially be heated to ~1 keV temperatures with large radiation temperature. Additionally, 2-D PIC simulations show large B-fields on both the front and back of these targets with B fields consistent with experiments using the petawatt at Rutherford Appleton Laboratory (Tatarakis, M. et al.: 2002c, Nature 415, 280).     

Environments of Supernova Remnants Which Contain Different Types of Neutron Star

Understanding the formation and evolution of massive galaxies provides important keys to constrain the baryon assembly processes in the ΛCDM hierarchical scenario. We review the main results obtained so far with the K20 and other recent near-IR surveys on the redshift distribution, the evolution of the luminosity function and luminosity density, the nature of old and dusty EROs, the evolution of the galaxy stellar mass function and the nature of luminous starbursts at z∼2 which may be the progenitors of the present-day massive spheroidal galaxies.     

Measuring the proper motion of the pulsar Geminga using γ-ray data

We have measured the right ascension of Geminga at different epochs by comparing the absolute phases between the different γ-ray observations. These values show that the right-ascension component of the proper motion of Geminga is 0.226±0.03 arcsec per year, which is consistent with that of G″, the most probable optical counterpart, thus independently confirming the correspondence between G″ and Geminga.     

超新星SN 1987A的热光度演化──内部中子星的贡献

本文介绍了超新星SN1987A爆发六年多来其热光度演化的研究情况．爆发后的前800天，观测的热光度曲线与由超新星爆发时合成的放射性元素的放射衰变加热模型符合得很好．但900天以后，观测的热光度曲线比考虑了所有放射性元素贡献后的理论曲线下降得还要缓慢．这可能表明有新的能源在起作用．我们认为这个新的能源可能是超新星爆发时产生的中子星的吸积．通过吸积超新星爆发时抛射气壳中小于逃逸速度的部分物质而增大SN1987A的热光度．这一模型能很好地解释900天以后的光度曲线的下降变级以及900至1200天之间光度曲线的凸起，这也为内部中子星的存在提供了间接的证据．     

Evolution of The Spin Periods of Neutron Stars in Low Mass X-ray Binaries

We present a numerical analysis of the spin evolution of neutron stars in low-mass X-ray binaries, trying to explain the discrepancy in the spin period distribution between observations of millisecond pulsars and theoretical results. In our calculations, we take account of possible effects of radiation pressure and irradiation-induced instability on the structure of the disk, and the evolution of the mass transfer rate, respectively. We report the following results: (1) The radiation pressure in the accretion disk leads to a slight increase of spin periods, and the variation of mass transfer rate caused by the neutron star irradiation can shorten the spin-down phase of evolution. (2) The calculated results of the model combining radiation pressure and irradiation show that the accretion is strongly limited by the radiation pressure in the high mass transfer phase. (3) The accreted mass and fastness parameter can affect the number of systems in the equilibrium state.     

Evolution of Pulsars with Energy Release in the Superfluid Core of a Neutron Star

The effect of a neutron-proton vortex system on the rotation dynamics of neutron stars is examined. The dynamics of the motion of a two component superfluid system in the core of a neutron star yields an equation for the evolution of the pulsar's rotation period. The spin down of the star owing to energy release at the core boundary, which is associated with a contraction of the length of the neutron vortex as it moves radially and magnetic energy of the vortical cluster is released, is taken into account. Evolutionary curves are constructed for pulsars with different magnetic fields and stellar radii. For certain values of the coefficient of friction between the superfluid and normal components in the core of the neutron star, at the end of its evolution a radio pulsar may become an anomalous x-ray pulsar or a source of soft gamma radiation with a period on the order of 10 seconds.     

毫秒脉冲星计时观测进展

在评述国际上毫秒脉冲星长期计时观测成果的基础上，比较了由毫秒脉冲星自转定义的脉冲星时PT与原子时AT的长期稳定度。毫秒脉冲星PSR B1855 09 15yr的长期稳定度优于原子时TAI—USNO，而接近原子时TAI—PTB；其短期稳定度主要受到计时观测误差的限制。毫秒脉冲星PSR J0437-47 1yr以上的稳定度明显优于上述两原子时系统。毫秒脉冲星PSR B193T 21和PSR J1713 07的长期稳定度受到低频噪声影响，但仍能对综合脉冲星时PTens的建立与保持作出贡献。另外，介绍和评述了国际上脉冲星计时阵的现状及发展。随着脉冲星计时阵的实旅，在脉冲星时间标准研究、原子时误差、太阳系历表误差研究和引力波探测方面将会取得重要成果；展望了国际上平方公里望远镜(SKA)在毫秒脉冲星计时观测方面的发展前景。     

Repeating fast radio bursts reveal the secret of pulsar magnetospheric activity

The puzzling mechanism of coherent radio emission remains unknown, but fortunately, repeating fast radio bursts (FRBs) provide a precious opportunity, with extremely bright subpulses created in a clear and vacuum-like pulsar magnetosphere. FRBs are millisecond-duration signals that are highly dispersed at distant galaxies but with uncertain physical origin(s). Coherent curvature radiation by bunches has already been proposed for repeating FRBs. The charged particles are created during central star's quakes, which can form bunches streaming out along curved magnetic field lines, so as to trigger FRBs. The nature of narrow-band radiation with time-frequency drifting can be a natural consequence that bunches could be observed at different times with different curvatures. Additionally, high linear-polarization can be seen if the line of sight is confined to the beam angle, whereas the emission could be highly circular-polarized if off-beam. It is also discussed that pulsar surface may be full of small hills (i.e., zits) which would help producing bulk of energetic bunches for repeating FRBs as well as for rotation-powered pulsars.     

Comparing Black Hole and Neutron Star Variability

There are remarkable similarities between the rapid X-ray variability of low-magnetic field neutron stars in low mass X-ray binaries, and that of black holes. In particular at frequencies < 100 Hz, their power spectra can be strikingly similar. The highest frequency phenomena (kilohertz QPOs, black hole high-frequency QPOs and neutron star hectohertz QPOs) are the ones that show most differences, perhaps because they originate closest to the compact object. Most variability components vary in frequency in correlation with one another, and the correlations once again are very similar across neutron stars and black holes – some extend even to white dwarfs. Although this does not strictly require that all phenomena whose frequencies are involved are caused by the same physics in all three source types, this does indicate that basic properties of the accretion flow which are the same in all three source types play an important role in generating at least some of the frequencies.     

Structure of the Magnetic Field of a Neutron Star

The magnetic field distribution in the superfluid, spherical, hadronic core of a rotating neutron star, which consists of vortex and vortex-free zones, is investigated. Due to the effect of entrainment of superconducting protons by rotating superfluid neutrons, a nonuniform magnetic field, the average value of which is constant, is formed in the vortex zone of the neutron star, directed parallel to the star's axis of rotation. It is shown that at the stellar surface, near the equatorial plane, there is a vortex-free zone of macroscopic size in which there is no magnetic field. The magnetic field near the boundaries of the vortex-free zone falls off exponentially with depth into the interior of this zone. This result essentially alters earlier concepts about the magnetic field distribution in the superfluid hadronic core of a neutron star. Outside the hadronic core the magnetic field has a dipole character with a magnetic moment on the order of 10³⁰ g×cm³.     

估算有中子星作伴星的黑洞质量

在本文中，我们讨论了由中子星和黑洞构成的密近双星系统的引力效应。首先，我们清楚地解释了引力辐射存在引起的轨道圆化，并估算了圆化的时间尺度。求解了围绕史瓦西黑洞作圆轨道运动的矢量进动方程，得到了一个精确解。由进动周期和中心黑洞的质量的关系，我们得到了估算中子星伴随的黑洞质量的方法。随后我们讨论了以中子星脉冲信号随自旋进动变化来寻找黑洞的方法。     

脉冲星时稳定度及可能应用

给出了毫秒脉冲星长期计时观测最新结果和脉冲星时与原子时频率稳定度的比较。指出脉冲星时频率稳定度的提高受到计时观测误差的限制,讨论了提高毫秒脉冲星计时观测精度的方法。随着脉冲星计时阵的实施,脉冲星时的应用已为期不远。可能的应用包括毫秒脉冲星与原子钟结合守时、建立综合脉冲星时和用脉冲星计时阵检测原子时误差等方面。     

Magnetic Field of a Neutron Star With Color Superconducting Quark Matter Core

The behaviour of the magnetic field of a neutron star with a superconducting quark matter core is investigated in the framework of the Ginzburg-Landau theory. We take into account the simultaneous coupling of the diquark condensate field to the usual magnetic and to the gluomagnetic gauge fields. We solve the Ginzburg-Landau equations by properly taking into account the boundary conditions, in particular, the gluon confinement condition. We found the distribution of the magnetic field in both the quark and hadronic phases of the neutron star and show that the magnetic field penetrates into the quark core in the form of quark vortices due to the presence of Meissner currents.     

中子星中心致密天体的双星起源

探讨了认为中心致密天体(CCO)起源于双星的可能性.首先, CCO与正常遗迹脉冲星有着相似的平均自旋周期,但CCO的平均表面磁场强度(B～5.4×10~(10)Gs)低于正常遗迹脉冲星(B～7.7×10~(12)Gs)～2个量级.同时,几乎所有的正常遗迹脉冲星均分布在爱丁顿吸积加速线以上,而CCO全部分布在自旋加速线以下.因此怀疑CCO可能起源于双星吸积加速过程.其次,基于中子星再加速理论,分析了CCO可能的双星演化过程:双星系统中, CCO以M～1017g·s~(-1)的吸积率,经过～106yr的时间共吸积△M～10~(-2)M⊙的物质,其自旋周期将会从P～10 s降低至P～0.1 s,表面磁场强度将会从B～10~(12)Gs降低至B～1010Gs.考虑到～106yr的演化时标远大于CCO遗迹的年龄(～0.3–7 kyr),猜想CCO可能是双星系统中第1颗恒星超新星爆发的产物,而第2颗恒星超新星爆发后双星解体,留下CCO和第2颗恒星的超新星遗迹.该模型预言在CCO附近可能存在一颗年轻的正常脉冲星(P～0.02 s, B～1012Gs),并期望未来的射电望远镜和高能探测器能够进行搜寻.     

Star complexes and a scenario for the evolution of spiral galaxies

The major features of star complexes as “building blocks” of the large-scale structure of spiral galaxies are presented and a scenario for spiral formation is suggested on this basis.     

Pulse phase dependence of the magnetar bursts

We report here results from a study of X-ray bursts from 3 magnetar candidates (SGR 1806-20, SGR 1900+14 and AXP 1E 2259+586). We have searched for a pulse phase dependence of the X-ray burst rate from these sources. X-ray light curves were obtained with the Proportional Counter Array on-board the Rossi X-ray Timing Explorer during the periods of intense burst activity in these sources. On detailed analysis of the three sources, we found a very significant burst rate for all pulsar phases. However, some locations appear to produce bursts slightly more often, rendering the non-isotropic distribution. Only in the case of SGR 1900+14, there is a clear pulse phase dependence of burst rate.     

国家授时中心40米射电望远镜Crab脉冲星周期跃变监测

脉冲星周期跃变是一种罕见的现象,是研究其内部结构的探针。针对2019年2月~12月国家授时中心昊平观测站40 m射电望远镜在脉冲星计时观测中监测Crab脉冲星的数据,采用脉冲星计时方法,用TEMPO2拟合程序进行分析。结果表明,Crab脉冲星在2019年7月23日(MJD 58687)附近发生了一次周期跃变现象,该跃变自转增量为Δv_g=5.33(4)×10^-7Hz,自转变化量为Δv_g/v=17.9(1)×10^-9,并伴随着恢复系数Q~0.88的指数恢复过程。此次Crab脉冲星周期跃变的监测及处理,证实了40 m射电望远镜对脉冲星的监测性能,同时为研究周期跃变的产生机理积累了样本。     

基于脉冲星的星载钟时间修正算法研究

讨论了一种对长期在轨运行的星载钟的钟差进行修正的方法,该方法以导航用毫秒脉冲星作为高稳定度频率源,采用卡尔曼最优估计算法对星载钟进行控制。仿真计算表明,该方法可以有效提高星载钟的长期频率稳定度,增强星载钟的长期自主运行能力。     

The Influence of a New Model of Progenitor Star on Supernova Explosion

By adopting the progenitor model proposed by Woosley in 2002 and using the program WZYW89, the process of explosion of type II supernovae with masses of 11−40M_⊙ is numerically simulated. The results of computation reveal that this new model can in different degrees affect the collapse and explosion of type II supernovae as well as the propagation of shock waves. Besides, the definitions of the primary energy of shock waves are also discussed.     

脉冲星时间特征和多星计时观测

在评介脉冲星时研究发展趋势的基础上,讨论了基于毫秒脉冲星自转的脉冲星时间的短期特征和长期稳定度,并对影响其稳定度的因素作了初步分析.50m射电望远镜计时观测的目的之一就是综合脉冲星时研究.对于50m望远镜计时观测的选星和由多星观测进行综合脉冲星时研究中的数据分析问题进行了讨论.