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1.
脉冲星脉冲到达时间观测系统建立在２５ｍ射电天线的１８ｃｍ波段上,消色散采用了２×１２８×２．８ＭＨｚ多通道滤波器和数字化器,数据采集系统由ＰＣ机完成,１９９９年５月至６月间建立了基于常温接收机的到达时间观测系统。观测到的最弱源的平均流量密度为４ｍＪｙ。 相似文献
2.
本文对１９９０年７月３０日云南天文台四波段（１．４２ＧＨｚ、２．００ＧＨｚ、２．８４ＧＨｚ和４．００ＧＨｚ）太阳射电高时间分辨率同步观测系统［１，２］所观测到的太阳射电大爆发进行了分析，对在１．４２ＧＨｚ、２．００ＧＨｚ、２．８４ＧＨｚ三个波段上观测到的大量尖峰辐射（ｍｓ—ｓｐｉｋｅｓ）作了关于寿命和强度的统计，最后，针对本次爆发中的ｍｓ—ｓｐｉｋｅｓ的特点做了一些讨论。 相似文献
3.
一个含有丰富快速精细结构的射电大爆发 总被引：2，自引：2，他引：0
本文对１９９０年７月３０日云南天文台四波段太阳射电高时间分辨率同步观测系统＾「１，２」所观测到的太阳射电大爆发进行了分析，对在１．４２ＧＨｚ，２．００ＧＨｚ，２．８４ＧＨｚ三个波段上观测到的大量尖峰辐射作了关于寿命和强度的统计，最后，针对本次爆发中的ｍｓ－ｓｐｉｋｅｓ的特点做了一些讨论。 相似文献
4.
蒋达西 《紫金山天文台台刊》1995,14(4):274-282
本对１９８４年４月－１９８５年４月在南京紫金山山上大人卫测点，用积分多普勒观测的二维单点定位资料进行了分析。并根据卫星来自ＳＥ、ＳＷ、ＮＥ、ＮＷ四个象限获取的资料，分别进行了归算和处理，结果精度如下：σφ（ＳＥ）＝３．７ｍ，σφ（ＳＷ）＝４．２ｍ σφ（ＮＥ）５．１ｍ，σφ（ＮＷ）＝６．５ｍ σλ（ＳＥ）＝４．９ｍ，σλ（ＳＷ）＝５．６ｍ σλ（ＮＥ）３．３ｍ，σλ（ＮＷ）＝４．０ｍ上述表达式中 相似文献
5.
四频率太阳射电高时间分辨率观测特征：微耀斑能量释放的证据 总被引：1，自引：0，他引：1
作为微耀斑能量释放的证据，本文扼要介绍了云南天文台“四频率太阳射电高时间分辨率同步观测系统”（１．４２，２．１３，２．８４和４．２６ＧＨｚ）１９８９年１２月－１９９３年４月的观测事例，包含低强度的毫秒尖峰辐射（ｍｓｓｐｉｋｅ），类尖峰辐射（ｓｐｉｋｅ－ｌｉｋｅ），快速脉动现象，两种新的快速精细结构──微波Ⅲ型爆和微波类斑点结构．统计了快速精细结构的寿命，在统计基础上分别以实例描述了各类现象的观测特征． 相似文献
6.
在紫金山天文台１３．７米望远镜２２ＧＨｚ系统的基础上，建立了２２ＧＨｚ太阳高时间分辨率的观测系统。本文介绍了在原系统基础上改造的波束／负载调制器和双温定标系统，以及为实现高时间分辨率而专门研制的ＱＪ－２ＡＧ高速后端和独立的微机数据采集系统。投入使用的２２ＧＨｚ太阳高时间分辨率观测系统在时间分辨率为１０ｍｓ时，灵敏度为０．０２ｓｆｕ，系统增益稳定性在全功率方式下为０．８％／３０分钟，数据丢失率小于１ 相似文献
7.
云南天文台“四波段（１．４２ＧＨｚ,２．１３ＧＨｚ,２．８４ＧＨｚ和４．２６ＧＨｚ）太阳射电高时间同步观测系统”在１９９０．１￣１９９４．１期间,观测到５个具有短时标漂移结构的射电爆发事件,也就是微波Ⅲ型爆发。本文从中选取较典型的１９９１年３月１３日事件,对Ⅲ型爆发的时间轮廓（持续时间,衰减时间）作了分析,并与米波,分米波和微波段其它观测结果作了一些比较,以求对长厘米￣短分米波段（微波低端）Ⅲ型爆 相似文献
8.
9.
云南天文台“四波段（１．４２ＧＨｚ,２．１３ＧＨｚ,２．８４ＧＨｚ和４．２６ＧＨｚ）太阳射电高时间同步观测系统”在１９９０．１～１９９４．１期间,观测到５个具有短时标漂移结构的射电爆发事件,也就是微波Ⅲ型爆发。本文从中选取较典型的１９９１年３月１３日事件,对Ⅲ型爆发的时间轮廓（持续时间,衰减时间）作了分析,并与米波,分米波和微波段其它观测结果作了一些比较,以求对长厘米～短分米波段（微波低端）Ⅲ型爆发的时间轮廓的特征有一个初步的了解,最后对爆发的物理参数作了估计。 相似文献
10.
根据北京天文台２．１６ｍ望远镜的有缝光谱观测，证认出位于１０ｈ５７ｍ４８．５ｓ＋４３°１６′１３″（１９５０．０）的一个ＲＯＳＡＴＸ射线源是一个ｚ＝０．３２的类星体。 相似文献
11.
S. V. Bogovalov D. V. Khangulyan A. V. Koldoba G. V. Ustyugova F. A. Aharonian 《Monthly notices of the Royal Astronomical Society》2008,387(1):63-72
In this paper, we present a detailed hydrodynamical study of the properties of the flow produced by the collision of a pulsar wind with the surrounding in a binary system. This work is the first attempt to simulate interaction of the ultrarelativistic flow (pulsar wind) with the non-relativistic stellar wind. Obtained results show that the wind collision could result in the formation of an 'unclosed' (at spatial scales comparable to the binary system size) pulsar wind termination shock even when the stellar wind ram pressure exceeds significantly the pulsar wind kinetic pressure. Moreover, the post-shock flow propagates in a rather narrow region, with very high bulk Lorentz factor (γ∼ 100). This flow acceleration is related to adiabatic losses which are purely hydrodynamical effects. Interestingly, in this particular case, no magnetic field is required for formation of the ultrarelativistic bulk outflow. The obtained results provide a new interpretation for the orbital variability of radio, X-ray and gamma-ray signals detected from binary pulsar system PSR B1259−63/SS2883. 相似文献
12.
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Δvg=5.33(4)×10-7Hz,自转变化量为Δvg/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。 相似文献
13.
Yang Ting-gao Tong Ming-lei Zhao Cheng-shi Gao Yu-ping 《Chinese Astronomy and Astrophysics》2019,43(1):93-100
The X-ray timing data for the Crab pulsar obtained by the Chinese X-ray pulsar navigation test satellite are processed and analyzed. The method to build the integrated and standard X-ray pulse profiles of the Crab pulsar by using the X-ray pulsar observation data and the satellite orbit data is described. The principle and algorithm for determining the pulsar's pulse time of arrival (toa) in the frequency domain are briefly introduced. The pulsar's pulse time of arrival is calculated by using the timing data of 50 min integration for each set of observational data. By the comparison between the observed Crab pulsar's pulse time of arrival at the solar system barycenter and that predicted with the Crab pulsar ephemeris, it is found that the timing accuracy is about 14 μs after the systematic error is removed by a quadratic polynomial fitting. 相似文献
14.
毫秒脉冲星在时间计量中的可能应用 总被引：1，自引：0，他引：1
在分析射电脉冲星的自转和时间尺度的基本特征及其相互之间的关系的基础上，讨论了毫秒脉冲星在时间工作中的可能应用。基于毫秒脉冲星的到达时间的测量，经过必要的时空转换、改正及参数拟合，可以建立脉冲星时及综合脉冲星时。虽然脉冲星时及综合脉冲星时对原子有所依赖，但它们，特别是综合脉冲星时，可以用来将原子时的准确度从一个时段传递到另一个时段，并可用来分析原子时的长期稳定度。另外，可以利用双星脉冲星的轨道运动的相位来定义一种动力学时间尺度－－双星脉冲星时。 相似文献
15.
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
16.
I.H. Stairs R.N. Manchester A.G. Lyne V.M. Kaspi † F. Camilo J.F. Bell N. D'Amico M. Kramer F. Crawford ‡ D.J. Morris A. Possenti N.P.F. McKay S.L. Lumsden L.E. Tacconi-Garman R.D. Cannon N.C. Hambly P.R. Wood 《Monthly notices of the Royal Astronomical Society》2001,325(3):979-988
We report on the discovery of a binary pulsar, PSR J1740−3052, during the Parkes multibeam survey. Timing observations of the 570-ms pulsar at Jodrell Bank and Parkes show that it is young, with a characteristic age of 350 kyr, and is in a 231-d, highly eccentric orbit with a companion whose mass exceeds 11 M⊙ . An accurate position for the pulsar was obtained using the Australia Telescope Compact Array. Near-infrared 2.2-μm observations made with the telescopes at the Siding Spring observatory reveal a late-type star coincident with the pulsar position. However, we do not believe that this star is the companion of the pulsar, because a typical star of this spectral type and required mass would extend beyond the orbit of the pulsar. Furthermore, the measured advance of periastron of the pulsar suggests a more compact companion, for example, a main-sequence star with radius only a few times that of the Sun. Such a companion is also more consistent with the small dispersion measure variations seen near periastron. Although we cannot conclusively rule out a black hole companion, we believe that the companion is probably an early B star, making the system similar to the binary PSR J0045−7319. 相似文献
17.
乌鲁木齐天文站自 1 999年研制完成 1 .5GHz频段室温双偏振消色散接收系统。 2 0 0 2年又完成 1 .5GHz频段致冷式双偏振消色散接收系统。我们成功地完成了第一个国际合作协议的任务。为在我国建立高灵敏度的观测脉冲星设备和取得优秀的脉冲星观测结果作出了贡献。为了进一步发展乌站脉冲星观测 ,第二个合作协议包括利用致冷式系统进行脉冲星大样本的监测和建立低频段的基带技术的消色散系统。 相似文献
18.
Ashish Asgekar Avinash A. Deshpande 《Monthly notices of the Royal Astronomical Society》2001,326(4):1249-1254
In the previous paper of this series, Deshpande & Rankin reported results regarding the sub-pulse drift phenomenon in pulsar B0943+10 at 430 and 111 MHz. This study has led to the identification of a stable system of sub-beams circulating around the magnetic axis of this star. Here, we present a single-pulse analysis of our observations of this pulsar at 35 MHz. The fluctuation properties seen at this low frequency, as well as our independent estimates of the number of sub-beams required and their circulation time, agree remarkably well with the reported behaviour at higher frequencies. We use the 'cartographic' transform mapping technique developed by Deshpande & Rankin in Paper I to study the emission pattern in the polar region of this pulsar. The significance of our results in the context of radio emission mechanisms is also discussed. 相似文献
19.
Nalini H. Issur 《Astrophysics and Space Science》2002,282(1):77-85
The Mauritius Radio Telescope (MRT) was designed to operate mainly as an imaging instrument to carry out a southern sky survey
at 150MHz. However, it has also been successfully used it for pulsar observations. In this paper, we give an overview of the
pulsar observing system we developed for use at MRT. Our pulsar receiver is of the ‘direct-recording’ type whereby most of
the data processing, including dedispersion is done completely offline. The various steps involved in this data processing
are also briefly described.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
The pulsar time defined by a single pulsar is affected by many kinds of noise sources. Its short-term and long-term degrees of stability are both not good enough. In order to weaken the influence of these noise sources on the single pulsar time, an appropriate algorithm can be adopted to make a synthesis of many single pulsar times, then the ensemble pulsar time is obtained, thereby increasing the long-term degree of stability of the ensemble pulsar time. In this article four kinds of algorithms of the ensemble pulsar time are introduced, i.e., the classical weighting algorithm, wavelet analysis algorithm, Wiener filtering algorithm and Wiener filtering algorithm in wavelet domain. These four algorithms are respectively applied to the timing residuals obtained from the observation of two millisecond pulsars, PSR B1855+09 and PSR B1937+21 made at the Arecibo Astronomical Observatory, and comparisons are carried out. 相似文献