共查询到19条相似文献，搜索用时 109 毫秒
1.
脉冲星时间特征和多星计时观测 总被引：1，自引：0，他引：1
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. 相似文献
2.
介绍上海天文台25 m射电望远镜首次单天线脉冲星观测。2010年4月23日,使用上海天文台位于佘山观测基地的25 m射电望远镜对脉冲星J0332+5434在L波段进行了观测,此次观测使用VLBI终端进行数据采集记录,通过对观测数据进行非相干消色散和周期折叠,成功获得目标源的平均轮廓。此次观测的成功,表明该天线具备开展单天线脉冲星观测的条件,并为上海天文台建设中的65 m天线的天文观测提供了参考,为将来自主研发脉冲星终端进行了技术储备。 相似文献
3.
简介了国际上脉冲星计时研究的成果。主要评述中国在脉冲星计时研究方面的进展和观点：某些ms脉冲星可以用作天然的高精度的频率标准源。ms脉冲星时(PTens)的长期稳定度随观测时间的加长而提高，同时，它具有寿命长，稳定、可靠、不需要维修等优点。尽早适时地建立专门用于测量ms脉冲星时(PFens)的脉冲星钟系统网络是有益的。我国正在建设用于脉冲星脉冲到达时间(TOA)测量的50m射电望远镜，和正在研究(FAST)500m射电望远镜。论述了脉冲星时间尺度的建立是可行的，脉冲星时和原子时可以“交叉比对，相互检验，并肩发展”。研究表明综合脉冲星时的长期稳定度明显优于原子时。阐述了把小波分析方法应用于时间尺度，研究结果比较传统方法有明显的优势。对国际间的合作提出建议。并展望了中国的脉冲星计时规划。 相似文献
4.
简介了国际上脉冲星计时研究的成果。主要评述中国在脉冲星计时研究方面的进展和观点:某些ms脉冲星可以用作天然的高精度的频率标准源。ms脉冲星时(PTens)的长期稳定度随观测时间的加长而提高,同时,它具有寿命长,稳定、可靠、不需要维修等优点。尽早适时地建立专门用于测量ms脉冲星时(PTens)的脉冲星钟系统网络是有益的。我国正在建设用于脉冲星脉冲到达时间(TOA)测量的50m射电望远镜,和正在研究(FAST)500m射电望远镜。论述了脉冲星时间尺度的建立是可行的,脉冲星时和原子时可以"交叉比对,相互检验,并肩发展"。研究表明综合脉冲星时的长期稳定度明显优于原子时。阐述了把小波分析方法应用于时间尺度,研究结果比较传统方法有明显的优势。对国际间的合作提出建议。并展望了中国的脉冲星计时规划。 相似文献
5.
《天文学进展》2017,(2)
脉冲星观测研究一直是新疆天文台的主要研究方向,未来建设的新疆110 m口径全可动射电望远镜(简称QTT)也将其作为主要研究方向之一。南山25 m射电望远镜当前使用的脉冲星单脉冲观测终端AFB已使用近20年,系统老化严重,为升级现有单脉冲观测系统,也为QTT的终端设计做预研,基于ROACH2研制了一套脉冲星观测系统。该系统采用氢钟与GPS时间同步以提供秒起始信号,对采样时钟计数并打入数据帧以获取精准时间间隔,两者合成即可获得精确时间信息;采用共享内存缓冲区,使数据在多进程间共享实现并行实时处理。该系统可用于脉冲星单脉冲或到达时间观测,也可用于脉冲星、RRAT或FRB等搜寻。已在南山进行单脉冲、长时间折叠、FRB实时搜寻等观测试验,试验数据表明该终端准确、稳定、可靠,已达到投入观测使用的要求。 相似文献
6.
7.
8.
脉冲星的偏振信息是理解脉冲星辐射区的重要手段，利用澳大利亚的64m射电望远镜进行大量的脉冲星观测，得到了一批脉冲星的偏振轮廓和偏振参数，编辑了几乎所有发表的脉冲星轮廓资料，系统总结了脉冲星圆偏辐射的规律，为理论上解释脉冲星辐射这一重要难题提供观测依据和物理限制，利用脉冲星作为探针，研究了银河系磁场结构和模型，确定了银河系BS磁场模型，发现了银河系上下反对称的环向磁场，并首次对星系尺度的发电机类型进行判别，证认出A0型发电机运行于银河系，发现了银晕中的垂直磁场和M31及银盘中的非常延展的磁场，探测到NGC2997星系中由内到外的旋涡磁场，并提出可能有两种发电机在这个星系的不同区域运行。 相似文献
9.
邱育海 《中国科学院上海天文台年刊》1995,(16):280-281
本文描述了密云综合孔径射电望远镜的相加系统，以及该系统将被应用于行星际闪烁观测、脉冲星观测、一维太阳高速扫描和射电源定标等工作。 相似文献
10.
蜘蛛脉冲星的发现是研究毫秒脉冲星演化的重要进展,它们被认为可能是孤立毫秒脉冲星的来源之一。蜘蛛脉冲星系统含有丰富的观测现象,其中最重要的就是脉冲星的掩食。掩食脉冲星的研究可以帮助理解脉冲双星的演化、球状星团的形成和星际介质等。介绍了近年来脉冲星掩食研究的主要进展,包括脉冲星的掩食特点,掩食脉冲星系统的统计和举例,并阐述了常用的掩食机制。在未来10年里,随着超高灵敏度和超快巡天速度的射电望远镜的投入使用,如平方公里阵列射电望远镜(Square Kilometre Array, SKA)等,掩食脉冲星的研究有望打开新局面,并对掩食机制理论的发展产生积极的影响,帮助解决一些未解之谜。 相似文献
11.
Yan-Wei Xie Jing-Bo Wang George Hobbs Jane Kaczmarek Di Li Jie Zhang Shi Dai Andrew Cameron Lei Zhang Chen-Chen Miao Mao Yuan Shen Wang Song-Bo Zhang Heng Xu Ren-Xin Xu 《天文和天体物理学研究(英文版)》2019,(7)
Flux densities are fundamental observational parameters that describe a pulsar. In the current pulsar catalogue, 27% of the listed radio pulsars have no flux density measurement in the 20 cm observing band. Here, we present the first such measurements for 32 pulsars observed employing the Parkes radio telescope. We have used both archival and new observations to make these measurements. Various schemes exist for measuring flux densities and we show how the measured flux densities vary between these methods and how the presence of radio-frequency interference will bias the flux density measurements. 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.
Na Wang R.N. Manchester Aili Yusup Xinji Wu Jin Zhang Maozheng Chen 《Astrophysics and Space Science》2001,278(1-2):57-60
Scintillation of pulsar radio emission provides information about the interstellar medium along the path to the pulsar and
the velocities of pulsars. It also affects the precision of pulse timing observations. Using a pulsar timing system developed
at the Urumqi Astronomical Observatory25 m telescope, we observed diffractive scintillation dynamic spectra for several strong
northern pulsars. This paper introduces the observing system and discusses the observational results.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Results of long time observations of the pulsar B0950+08 are given.These observations were carried out at the LPA radio telescope at the frequency of 111 MHz fr... 相似文献
15.
N. N. Kalinichenko 《Astrophysics and Space Science》2009,319(2-4):131-138
Interplanetary scintillation observations of eleven supernova remnants and the pulsar J1939+2134, around which the existence of a supernova remnant remains obscure, were carried out with the largest in the world decameter radio telescope UTR-2 at 20, 25 and 30 MHz to determine if any of them contain compact radio sources with the angular size θ<5″. The sample included the young Galactic remnants and the other powerful SNRs. The interplanetary scintillations of the compact radio source in the Crab Nebula associated with the well-known pulsar J0534+2200 and the pulsar J1939+2134 were observed. Apart from the Crab Nebula, we have not detected a compact radio source in supernova remnants with the angular size θ<5″ and the flux density more than 10 Jy. The observations do not confirm the existence of the low frequency compact source in Cassiopeia A that has remained controversial. 相似文献
16.
A. G. Lyne F. Camilo R. N. Manchester J. F. Bell V. M. Kaspi N. D'Amico N. P. F. McKay F. Crawford D. J. Morris D. C. Sheppard I. H. Stairs 《Monthly notices of the Royal Astronomical Society》2000,312(4):698-702
We are undertaking a high-frequency survey of the Galactic plane for radio pulsars, using the 13-element multibeam receiver on the 64-m Parkes radio telescope. We describe briefly the survey system and some of the initial results. PSR J1811−1736, one of the first pulsars discovered with this system, has a rotation period of 104 ms. Subsequent timing observations using the 76-m radio telescope at Jodrell Bank show that it is in an 18.8-d, highly eccentric binary orbit. We have measured the rate of advance of periastron which indicates a total system mass of 2.6±0.9 M⊙ , and the minimum companion mass is about 0.7 M⊙ . This, the high orbital eccentricity and the recycled nature of the pulsar suggest that this system is composed of two neutron stars, only the fourth or fifth such system known in the disc of the Galaxy. 相似文献
17.
Radio telescopes are a scarce resource designed to provide experimental data for astrophysical research, and various studies have focused on the design of observing schedules that make optimal use of available telescope time. We consider strategies for minimising the time required to observe a fixed set of pulsars, which provides an excellent example of scheduling in an unpredictable environment. First, owing to scintillation, the intensity of a pulsar signal is variable and random; therefore, the decision to abort or prolong an observation can be made only after some fraction of the scheduled observation has been completed. Second, observations may be interrupted by radio frequency interference or when the source sets below the horizon. Some sources are visible for more or less time depending on their declination and the latitude of the observing telescope. Formulating the problem in these terms leads to a highly dynamic shortest path problem with uncertainty. Unlike other documented telescope scheduling approaches, we demonstrate how a simple earliest setting policy achieves sets of pulsar observations in a rather short timespan. The policy is fast to apply due to a novel algorithm that pre-calculates the subset of next candidates before the end of the current integration. Our simulation also clarifies that the uncertainty arising from the scintillation (signal strength) encountered on arrival adds significantly to the variation in overall durations and that different hourly start times can favour or hamper the progress of a set of observations. 相似文献
18.
We determined the features of pulsars that were disregarded in standard amplitude-calibration procedures for VLBI observations. We suggest additional amplitude-calibration methods. These methods were used to process the VLBI observations of the pulsar PSR B0329+54 carried out with the HALCA ground—space interferometer. Data from the space radio telescope are corrected for a nonuniform reception band. We estimated the diameter of the scattering disk for this pulsar at a frequency of 1600 MHz: \( < 1\mathop .\limits^{''} 8 \times 10^{ - 3}\). 相似文献
19.
Alex Wolszczan 《New Astronomy Reviews》2012,56(1):2-8
In this paper I recount the events which have led to the discovery of the first planets beyond the Solar System. The two planets circling an old neutron star, the 6.2 ms pulsar PSR B1257+12, were discovered in 1991 with the 1000 ft Arecibo radio telescope. The pulsar itself was detected by a large, all-sky survey conducted during the telescope maintenance period in early 1990. The subsequent timing observations have shown that the only plausible explanation of the variability of pulse arrival times of PSR B1257+12 was the existence of at least two terrestrial-mass planets around it. The third, Moon-mass planet in the system was detected in 1994, along with the measurement of perturbations resulting from a near 3:2 mean motion resonance between the two more massive bodies, which has provided the confirmation of a planetary origin of the observed variations of pulse arrival times. Further observations and analyses have resulted in an unambiguous measurement of orbital inclinations and masses of the planets in 2003. The measured approximate coplanarity of the orbits along with the inner solar system – like dynamical properties of the pulsar planets strongly suggest their origin in a protoplanetary disk, just like in the case of planets around normal stars. The existence of such a system predicts that rocky, Earth-mass planets should be common around various kinds of stars. 相似文献