脉冲星磁偶极辐射模型的修正

本讨论了脉冲星磁偶极辐射模型所取得的成就和存在的困难，针对不足之处对磁偶极模型进行修正。从统计上得到修正因子与周期变率的幂律关系。由修正后的磁场强度得出其衰减时标大于１０＾８年，这与有关的理论研究结果一致。修正后的磁偶极模型给出周期变率和周期的新关系为Ｐ∝Ｐ＾－３图中加速线以上的资料的统计拟合方程一致。     

一颗新的γ射线脉冲星：PSR0740－28

本文作者对ＣＯＳ－Ｂ卫星的两次观测数据进行了周期折叠分析，获得了来自ＰＳＲ０７４０－２８方向上的γ光子的周期位相脉冲结构．从两次不同观测数据中获得的相位图具有相似的结构，其对应的周期和周期变率值都在射电预期值附近；显著性分析表明，随机出现上述两个位相结构的概率不大于２×１０－５．由此我们相信ＰＳＲ０７４０－２８是一颗新的γ射线脉冲星．     

黑子半影内偶极运动磁特征的Hinode观测研究

利用Hinode卫星观测的单色像和磁图,对出现在黑子半影内的35对偶极运动磁特征进行形态特征、运动速度以及低层太阳大气响应3方面的研究,得出以下结论:(1)偶极运动磁特征正负两极成对出现在黑子半影较垂直的磁场之间并向着半影外边界运动,间接验证了偶极运动磁特征起源于黑子半影水平磁场,在2-8小时的时间间隔内,同一位置上会反复出现形态特征和运动速度相似的偶极运动磁特征,为海蛇状磁力线模型提供了证据支持. (2)光球和色球在偶极运动磁特征向外运动过程中会出现增亮,说明偶极运动磁特征会加热中低层太阳大气.(3)偶极运动磁特征的出现位置和半影磁场结构分布符合非梳子状黑子半影结构特征.     

日冕物质抛射的中性电流片及边源辐射对

利用日本阳光卫星上的软X－射线望远镜，硬X－射线望远镜和野边山射电日像仪1998年4月23日观测资料，对软X－射线日冕物质抛射和射电Ⅳ型爆发进行了综合研究，获得了下列有意义的结果。在2个磁偶极源之间发现了磁容带和少数的激活源。激活源将磁容带变成磁能带的过程，正是中性电流片的形成过程以及激发能量和发亮物质向它集中的过程。当2个磁偶极源被磁能带接通时，则中性电流片形成，并且发生软X－射线日冕物质抛射。物质抛射不仅从中性电流片处升起，也从整个磁能带上升起。软X－射线日冕物质抛射环具有2个足点，它们正是2个磁偶极源。膨胀环的头总是倾向于弱源的足点，因为它是来自2个足点磁压的平衡点。因此它的轨迹是中性线，由中性线便可确定中性电流片的位置。最后，发现了磁能带上中性电流片的边缘辐射对。     

中子星的热演化和磁衰减

本研究了中子星的热演化，自转演化和磁场演化的相互影响，考虑了一个自洽模型，中子星因磁偶极辐射而自转减慢，在内部产生某些加热过程，中子星磁场通过壳层的欧姆耗散来衰减。结果表明，磁场衰减提高了加热过程的重要性，相反，加热效应减慢了磁衰减，因此可以得出，中子星的热，自转和磁场也许不是独立演化的，不仅如此，这些演化与初始条件有关，因此，人们也许可以从射电和Ｘ射线观测对脉冲星年龄，初始磁场和周期给出某些限     

中子星的热演化和磁衰减

本文研究了中子星的热演化、自转演化和磁场演化的相互影响．考虑了一个自洽模型：中子星因磁偶极辐射而自转减慢，在内部产生某些加热过程，中子星磁场通过壳层的欧姆耗散来衰减．结果表明，磁场衰减提高了加热过程的重要性；相反，加热效应减慢了磁衰减．因此可以得出，中子星的热、自转和磁场也许不是独立演化的．不仅如此，这些演化与初始条件有关，因此，人们也许可以从射电和Ｘ射线观测对脉冲星年龄、初始磁场和周期给出某些限制．     

1998年4月23日发生在日面边缘上的软X射线日冕物质抛射

使用Yohkoh卫星上的SXT／HXT和Nobeyama射电日像仪（NoRH）观测资料，对1998年4月23日发生在日面东南边缘上的软X射线日冕物质抛射（CME）作了分析研究，结果表明，软X射线CME具有两个磁偶极源（MDSs）。在两个磁偶极源之间有一个磁容带（MCB）、一个中性电流片9NCS）和少有的激活源（ASs）。在磁容带被激活源变成磁能带期间，物质和能量都向NCS集中，这正是NCS形成的过程。当两磁偶极源被MEB接通时，NCS形成，并且CME发生，物质抛射不仅从NCS处升起，而且从整个MEB上升起，CME膨胀环具有两个足点，它们正是两个磁偶极源，膨胀环的头总是倾向于弱源的足点。头的轨迹是中性线，由中性线也可以确认NCS的位置。     

K－P关系和射电脉冲星辐射束宽度的估计

从极冠模型出发，利用观测参数Ｋ和辐射锥角的关系，通过研究Ｋ－Ｐ关系导出了对确定辐射区参数有重要意义的辐射束宽和周期的关系。给出了一种估计辐射束宽度和磁倾角的方法。     

反常X射线脉冲星的研究进展

反常X射线脉冲星（Anomalous X-ra Pulsars，简称AXP）是一类特殊的X射线源。与X射线脉冲星（通常处于大质量X射线双星系统中）相比，它们具有以下特征：X射线谱较软、光度低页稳定（≈10^27－10^29J.s^-1）、自转周期集中在10s左右稳定增长、迄今没有找到它们的光学、红外、射电的对应体、有一些可能戌超新星遗迹成协等。由观测到的自转周期变化可以确定它们的自转能损不足以提供有X射线辐射。解释AXP能源机制的理论模型目前主要有两大类：在吸积模型中，AXP被认为具有正常磁场强度（≈10^8T）的中子量，物质吸积提供X射线辐射原能源，并造成中子星的自转变化；另一种观点认为AXP是具有超强磁场（≈10^10-10^11T）的中子量（即磁星），其辐射能源来自它们巨大的磁或残余的热能，观测到的自转周期及其变化被归因子中子星的磁偶极辐射和物质抛射。两种模型各有优缺点，但目前看来观测事实对磁星模型较为有利。为了进一步明确AXP的性质，提供解释它们能源机制的线索，在介绍AXP的基本观测特征和理论解释的基础上，还将AXP与射电脉冲星、特强磁场射电脉冲量、射电宁静脉冲星侯选体及软γ射线复现源分别进行了比较。     

K—P关系和和射电脉冲星辐射束宽度的估计

从极冠模型出发，利用观测参数Ｋ和辐射锥角的关系，通过研究Ｋ－Ｐ关系导出了对确定辐射区参数有重要意义的辐射束宽和周期的关系。给出了一种估计辐射束宽度和磁倾角的方法。     

A modified dipole emission model of pulsars

The successes and shortcomings of the magnetic dipole emission model of pulsars are reviewed and a modification of the model presented. A power-law relation is found statistically between the modifying factor and the time derivative of the period. The decay time scale of the modified field is greater than 10⁸ yr, consistent with the theoretical results. The relation given by the modified model is , which is just the observed gradient in the empirical plot above the spinning-up line.     

Reanalysis of GU miniarray data using CORSIKA

The GU miniarray is a ultra high energy cosmic ray (UHECR) detector consisting of eight plastic scintillators of carpet area 2 m², each viewed by fast PMTs. It is used to detect Giant EAS by the method of time spread measurement of secondary particles produced in the atmosphere. The energies of the air showers have been reestimated using CORSIKA program. As in the original analysis the Cosmic Ray energy was determined via its relation to the ground level parameter N_s, the shower size. This relation was obtained previously through a best fit relation in agreement with QGS model and Yakutsk data. In this work we use CORSIKA code with QGSJET model of high energy hadronic interactions to simulate miniarray data leading to a modified relation between primary energy and shower size. A revised energy spectrum is reported for 10¹⁷–10¹⁹ eV primary energy.     

A positional comparison between coronal mass ejection events and solar type II bursts

An investigation is made to determine the positional relation between the leading edge of the coronal mass ejection (CME) and the source region of associated solar type II radio bursts. A preliminary relation between the optical and radio activity was first established for each event using projected starting times and positional data. Height - time plots were then deduced for the radio activity using radiospectrograph observations in conjunction with a variety of coronal density models. These plots were then compared with height - time plots for the leading edge of the associated CME events, which has been observed with the SOLWIND experiment aboard the P78-1 satellite. In 31 well-observed events a total of 13 (42%) had type II bursts which could confidently be placed near the leading edge of the CME. In these events the density model which gave the best agreement between CME and type II positions was five times the Saito (1970) quiet Sun model. The existence of these closely related events was further confirmed by direct positional comparisons for the event of 1979, May 4. In a further nine events the type II burst was seen within the CME but was located well behind the leading edge, suggesting that they were created by a blast wave. The remaining nine events had height - time plots which could not be accurately compared. The observations are discussed in relation to models for the CME and type II activity. We suggest that the type II is generated when the shock wave is formed within the closed field structure near the leading edge of the CME or, in the case of a blast wave, interacts with closed fields in the body of the transient.     

Effect of modified Chaplygin gas in anisotropic universe

In this work, we have studied the model of modified Chaplygin gas and its role in accelerating phase of the universe for anisotropic model. We have assumed that the equation of state of this modified model is valid from the radiation era to ΛCDM model. We have obtained the possible relation between the hessence and the modified Chaplygin gas. We have also use the statefinder parameters for characterize different phase of the universe diagrammatically.     

长γ暴时域功率密度谱与光度的强相关

提供一个基于光变曲线的长γ暴光度的估计量．对BASTE记录到的12个已知红移的γ暴，利用时域上的时变分析方法计算了各暴的功率密度谱，用功率密度的峰值P表征光变曲线变化的剧烈程度．通过拟合发现在共动坐标系P与γ暴的各向同性峰值光度L之间存在着相关关系．这是继Norris等和Reichart等发现时间延迟与光度、变化率与光度的相关性之后又一个γ暴时变特征量与其光度之间的相关关系．     

NLTE models of line-driven stellar winds – III. Influence of X-ray radiation on wind structure of O stars

We study the influence of X-rays on the wind structure of selected O stars. For this purpose we use our non-local thermodynamic equilibrium (NLTE) wind code with inclusion of additional artificial source of X-rays, assumed to originate in the wind shocks.
We show that the influence of shock X-ray emission on wind mass-loss rate is relatively small. Wind terminal velocity may be slightly influenced by the presence of strong X-ray sources, especially for stars cooler than   T _eff≲ 35 000 K  .
We discuss the origin of the   L _X/ L ∼ 10⁻⁷  relation. For stars with thick wind this relation can be explained assuming that the cooling time depends on wind density. Stars with optically thin winds exhibiting the 'weak wind problem' display enhanced X-ray emission which may be connected with large shock cooling length. We propose that this effect can explain the 'weak wind problem'.
Inclusion of X-rays leads to a better agreement of the model ionization structure with observations. However, we do not find any significant influence of X-rays on P  v ionization fraction implying that the presence of X-rays cannot explain the P  v problem.
We study the implications of modified ionization equilibrium due to shock emission on the line transfer in the X-ray region. We conclude that the X-ray line profiles of helium-like ions may be affected by the line absorption within the cool wind.     

ALUMINUM-26 AS A PLANETOID HEAT SOURCE IN THE EARLY SOLAR SYSTEM

The results of thermal model calculations which assume ²⁶Al as a heat source are presented. The relation between ²⁶Al content, the maximum central temperature obtained, and the time interval after formation until central cooling commences is elucidated. Because of the heating times required, these results constrain maximum permissible planetoid dimensions more severely than do previous calculations which assume a high initial temperature.     

Cluster formation and the Sunyaev–Zel'dovich power spectrum in modified gravity: the case of a phenomenologically extended DGP model

We investigate the effect of modified gravity on cluster abundance and the Sunyaev–Zel'dovich (SZ) angular power spectrum. Our modified gravity is based on a phenomenological extension of the Dvali–Gabadadze–Porrati model which includes two free parameters characterizing deviation from Λ cold dark matter cosmology. Assuming that Birkhoff's theorem gives a reasonable approximation, we study the spherical collapse model of structure formation and show that while the growth function changes to some extent, modified gravity gives rise to no significant change in the linear density contrast at collapse time. The growth function is enhanced in the so called normal branch, while in the 'self-accelerating' branch it is suppressed. The SZ angular power spectrum is computed in the normal branch, which allows us to put observational constraints on the parameters of the modified gravity model using small scale cosmic microwave background observation data.     

Nonlinear parametric instability and millisecond solar radio spikes

A model of nonlinear parametric instability (NLPI) modulation is suggested to explain the millisecond spikes in solar decimetric radio emission. The radio emission energy will periodically transfer to two other waves, and the intensity of the radio emission will be modified by NLPI processes in the corona, when the matching conditions of three-wave coupling are satisfied. This model can simultaneously explain the duration of spikes, why the millisecond spikes have not been observed in other solar radio emission, and the relation between the duration of the spikes and the intensity and the frequency of the radio emission as well.