Outer-magnetospheric model for Vela-like pulsars: formation of sub-GeV spectrum     

J. Takata  S. Shibata  K. Hirotani 《Monthly notices of the Royal Astronomical Society》2004,348(1):241-249

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Far-infrared and submillimetre observations of the Crab nebula     

D. A. Green  R. J. Tuffs  C. C. Popescu 《Monthly notices of the Royal Astronomical Society》2004,355(4):1315-1326

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脉冲星导航发展概要     

周城宏  钱卫平  郭军海  赵华 《南京气象学院学报》2015,7(3):241-246

随着空间探测任务的纵向深度发展,基于地基设备和操作的现有导航模式无法胜任未来的任务需求,利用遥远宇宙中脉冲星辐射信号信息的脉冲星导航为深空飞行器的精密定轨开辟了新的发展方向.文章介绍了脉冲星成因及辐射机制,在分析现有通用导航模式特点及其在深空任务中的局限性的基础上,阐述X射线脉冲星自主导航原理,对脉冲星导航方法以及X射线探测器等关键技术的发展进行了介绍,最后,对射电脉冲星导航进行了初步探讨.  相似文献   

Radio-Loud and Radio-Quiet Gamma-Ray Pulsars from the Galaxy and the Gould Belt     

P. L. Gonthier  R. Van Guilder  A. K. Harding  I. A. Grenier  C. A. Perrot 《Astrophysics and Space Science》2005,297(1-4):71-80

We present results of a population synthesis study of radio-loud and radio-quiet γ-ray pulsars from the Galactic plane and the Gould Belt. The simulation includes the Parkes multibeam pulsar survey, realistic beam geometries for radio and γ-ray emission from neutron stars and the new electron density model of Cordes and Lazio. Normalizing to the number of radio pulsars observed by a set of nine radio surveys, the simulation suggests a neutron star birth rate of 1.4 neutron stars per century in the Galactic plane. In addition, the simulation predicts 19 radio-loud and 7 radio-quiet γ-ray pulsars from the plane that EGRET should have observed as point sources. Assuming that during the last 5 Myr the Gould Belt produced 100 neutron stars, only 10 of these would be observed as radio pulsars with three radio-loud and four radio-quiet γ-ray pulsars observed by EGRET. These results are in general agreement with the recent number of about 25 EGRET error boxes that contain Parkes radio pulsars. Since the Gould Belt pulsars are relatively close by, the selection of EGRET radio-quiet γ-ray pulsars strongly favors large impact angles, β, in the viewing geometry where the off-beam emission from curvature radiation provides the γ-ray flux. Therefore, the simulated EGRET radio-quiet γ-ray pulsars, being young and nearby, most closely reflect the current shape of the Gould Belt suggesting that such sources may significantly contribute to the EGRET unidentified γ-ray sources correlated with the Gould Belt.  相似文献   

脉冲星在空间飞行器定位中的应用     

杨廷高  南仁东  金乘进  甘恒谦 《天文学进展》2007,25(3):249-261

利用脉冲星钟模型能高精度地预报脉冲星脉冲到达太阳系质心的时间。基于脉冲星时、空参考架可实现各类空间飞行器的自主导航。讨论了脉冲星钟的模型和脉冲星导航系统的框架结构,描述了脉冲星导航的基本原理和算法。指出脉冲星导航系统对脉冲星脉冲到达探测器时刻的测量精度,是决定空间飞行器位置解算精度的关键因素。脉冲星导航观测采用的原子钟如果足够稳定,则空间飞行器位置的解算方法可以简化。在脉冲星导航系统计时观测精度达到或优于几十微秒量级时,脉冲星视差、相对论效应的影响是不可忽略的。对脉冲星导航系统开发设计中的关键技术和进一步研究的主要问题进行了初步分析和讨论。  相似文献   

Synchro－Curvature　Radiation──弯曲磁场中一种新的、更普遍的辐射     

张家铝  郑广生 《天文学报》1995,(4)

Ｓｙｎｃｈｒｏ－ＣｕｒｖａｔｕｒｅＲａｄｉａｔｉｏｎ──弯曲磁场中一种新的、更普遍的辐射张家铝（中国科技大学天体物理中心合肥２３００２６）郑广生（香港大学物理系）关键词同步辐射，曲率辐射，脉冲星磁层在脉冲星的辐射模型中，同步辐射和曲率辐射占有极其重要...  相似文献   

K－P关系和射电脉冲星辐射束宽度的估计     

吴鑫基 《中国天文和天体物理学报》1995,(1)

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。  相似文献   

Taphonomy of decapod crustacean cuticle and its effect on the appearance as exemplified by new and known taxa from the Cretaceous–Danian crab Caloxanthus     

《Cretaceous Research》2015

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Repeating fast radio bursts reveal the secret of pulsar magnetospheric activity     

Renxin Xu  Weiyang Wang 《Astronomische Nachrichten》2024,345(2-3):e230153

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.  相似文献   

The micro-glitch in PSR B1821−24: a case for a strange pulsar?     

Raka Dona Ray Mandal  Sushan Konar  Mira Dey  Jishnu Dey 《Monthly notices of the Royal Astronomical Society》2009,399(2):822-826

The single glitch observed in PSR B1821−24, a millisecond pulsar in M28, is unusual on two counts. First, the magnitude of this glitch is at least an order of magnitude smaller  (Δν/ν∼ 10⁻¹¹)  than the smallest glitch observed to date. Secondly, all other glitching pulsars have strong magnetic fields with   B ≳ 10¹¹ G  and are young, whereas PSR B1821−24 is an old recycled pulsar with a field strength of  2.25 × 10⁹ G  . We have earlier suggested that some of the recycled pulsars could actually be strange quark stars. In this work, we argue that the crustal properties of such a strange pulsar are just right to give rise to a glitch of this magnitude, explaining the scarcity of larger glitches in millisecond pulsars.  相似文献