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1.
从ROSAT PSPC观测数据中我国发现了与PSR0355+54相关联的脉冲星X射线喷流存在的证据。这是一个与脉冲星自行方向相反的长度为12′的近似线性的辐射特征。假设喷流具有PSR0355+54相同的距离和星际吸收,而其能谱是谱指数为-0.5的幂律谱,可导出喷流的光度为2.48±0.83×10^24J/S。喷流中的平均磁场约为7.9×10^-9T,典型的电子能量为2.1×10^7MeV。 相似文献
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本文利用COS-B卫星观测资料对CGRO卫星新近发现的一颗γ射线脉冲星进行了守时性分析,得到了显著的周期结构,这个结果对PSR1055-52是一颗γ射线脉冲星提供了新的、独立的证认,本文对普遍公认的六颗γ射线脉冲星提供了新的、独立的证认。本文对普遍公认的六颗γ射线脉冲星也作了比较和讨论。 相似文献
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本文利用COS-B卫星观测资料对CGRO卫星新近发现的一颗γ射线脉冲星进行了守时性分析,得到了显著的周期结构。这个结果对PSR1055-52是一颗γ射线脉冲星提供了新的、独立的证认,本文对普遍公认的六颗γ射线脉冲星也作了比较和讨论。 相似文献
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1998年9月20日,伦琴X射线天文卫星(ROSAT)在指向转换过程中扫过太阳附近,结果来自太阳的强烈X射线烧毁了其上的高分辨成像仪(HRI)。此后,在1998年12月,ROSAT上的另一个主要探测器位置灵敏正比计数器(PSPC)利用剩余的少量气体进... 相似文献
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射电脉冲星周期跃变被认为是研究中子星内部结构和状态的极好探针。脉冲星高频巡天发现了一批年青脉冲星,脉冲星周期跃变的观测研究也有了飞快进展。至少发现了25颗有跃变现象的脉冲星(简称跃变脉冲星)和76次跃变事件。PSRJ0835-4510是目前已有跃变脉冲星活动参数最高的,PSRJ1341-62220的跃变活动最频繁,而PSRJ1614-5047在1995年发生的跃变是规模最大的,不同脉冲星的跃变事件 相似文献
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在乌鲁木齐天文站25米天线上进行的脉冲星观测 总被引:3,自引:0,他引:3
1996年1月,由北京天文台、北京大学、乌鲁木齐天文站组成的研究小组完成了乌鲁木齐天文站25m天线的脉冲星观测系统,取得了一些脉冲星的观测结果。共成功地观测了8颗脉冲星,得到4颗脉冲星的轮廓图;还观测到PS1133+16的反常模式。乌鲁木齐天文站将成为我国重要的脉冲星观测基地。 相似文献
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脉冲星PSR B0329+54的多波段观测 总被引:2,自引:0,他引:2
给出1999年3月12日至6月8日,使用国家天文观测中心乌鲁木齐南山站25m射电望远镜在0.327GHz,1.5GHz,2.3GHz,4.8GHz和8.4GHz频段,对脉冲星PSRB0329+54进行的多波段观测结果,PSRB0329+54的辐射呈幂律谱,并出现频谱转折现象,低频段谱指数为1.59,高频段为2.45,平均谱指数为1.72五个频段上的平均脉冲轮廓的角宽度和二个民分峰值间的角宽度都随频 相似文献
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利用ROSATVLA方法筛选,从ROSATX射线源中选出了一批新的BLLac天体和类星体的候选体.1996年12月8日至17日,利用北京天文台2.16m望远镜和OMR摄谱仪,对这批新候选体进行了光谱认证.经SUN工作站处理,又发现了5个新的X选类星体和1个Seyfert星系.此外,在扩大光谱波长覆盖范围到8500的条件下,重新观测了作者去年所发现的BLLac天体,结果发现2318+304在7259处有一很强的Hα6563+[NI]6548,6583发射线.因此,可以确定2318+304是一个类星体,而不是一个BLLac天体. 相似文献
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Chetana Jain Biswajit Paul Kaustubh Joshi Anjan Dutta Harsha Raichur 《Journal of Astrophysics and Astronomy》2007,28(4):175-184
We report here results from a new search for orbital motion of the accretion powered X-ray pulsar 4U 1626–67 using two different
analysis techniques. X-ray light curve obtained with the Proportional Counter Array of the Rossi X-ray Timing Explorer during
a long observation carried out in February 1996, was used in this work. The spin period and the local period derivative were
first determined from the broad 2–60 keV energy band light curve and these were used for all subsequent timing analysis. In
the first technique, the orbital phase dependent pulse arrival times were determined for different trial orbital periods in
the range of 500 to 10,000 s. We have determined a 3σ upper limit of 13 lt-ms on the projected semimajor axis of the orbit of the neutron star for most of the orbital period range,
while in some narrow orbital period ranges, covering about 10% of the total orbital period range, it is 20lt-ms. In the second
method, we have measured the pulse arrival times at intervals of 100 s over the entire duration of the observation. The pulse
arrival time data were used to put an upper limit on any periodic arrival time delay using the Lomb-Scargle periodogram. We
have obtained a similar upper limit of 10 lt-ms using the second method over the orbital period range of 500–10,000 s. This
puts very stringent upper limits for the mass of the compact object except for the unlikely case of a complete face-on orientation
of the binary system with respect to our line-of-sight. In the light of this measurement and the earlier reports, we discuss
the possibility of this system being a neutron star with a supernovae fall-back accretion disk. 相似文献
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C.A. Green 《Planetary and Space Science》1979,27(1):63-77
An analysis is made of giant pulsation (Pg) data recorded at ground stations in the Northern Auroral Zone in Scandanavia (mainly at Tromsø, L = 6.4 and Kiruna, L = 5.5) during the period September 1976 to December 1977. They are shown to have a meridional variation of amplitude and polarization consistent with a field line resonance structure and their vertical component behaviour suggests that they also have a rapid azimuthal phase variation. Limited data from conjugate stations at L = 4.4 are used to show that Pg's are odd mode oscillations of the field line. Pg's are equated to the observation of a unique compressional wave in space at synchronous orbit and it is suggested that they result from the drift wave instability of the compressional Alfven wave at the outer edge of the quiet time ring current. 相似文献
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Molowny-Horas Roberto Oliver Ramón Ballester José Luis Baudin Frédéric 《Solar physics》1997,172(1-2):181-188
We report on the observation of Doppler oscillations in a quiescent limb prominence. Fourier analysis of the data reveals an oscillatory period of 7.5 min, whose phase varies linearly at 16 consecutive points (7280 km) along the slit. This yields an upper limit for the perturbation wavelength of 20000 km. Wavelet analysis confirms the above period and indicates an oscillation lifetime of 12 min. Moreover, the disturbance appears to travel at a speed greater than 4.4 km s-1. A comparison of these results with the predictions of some theoretical models is made. 相似文献
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We present a radiometric observation of asteroid 1976 AA, and formulate a simple model for the infrared thermal phase function so that our data can be compared with similar measurements made at different phase angles. The radiometric diameter of 1976 AA from our observation is 940+200?100 meters and the geometric albedo is 0.18 ± 0.06, in satisfactory agreement with another published radiometric observation. 相似文献
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We made a period folding analysis on two sets of COS-B observations and obtained a clearly pulsed phase structure in the γ-ray photons from the direction of PSR 0740-28. The phase diagrams from the two different data sets have a similar structure and the period and period rate are close to radio expectations. The probability of the two phase structures arising by chance is less than 2×10−5. Hence we believe PSR 0740-28 is a new γ-ray pulsar. 相似文献
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N. O. Miller 《Solar System Research》2011,45(4):342-353
The work studies the Chandler component of polar motion, obtained from variations in the Pulkovo latitude over 170 years (1840–2009).
To extend the time series of variations in the Pulkovo latitude back into the past until 1840, we used the first Pulkov observations
on the basis of the Reynolds transit instrument in the prime vertical and on the basis of large vertical Ertel circle. We
employed different methods of analysis of nonstationary time series, such as wavelet analysis, methods of bandpass filtering,
singular spectral analysis, and Fourier and Hilbert transforms. Changes in the Pulkovo latitude from 1904–2006, as inferred
from ZTF-135 observations and as calculated from international data, were compared. It was shown that time changes in the
amplitude and phase of Chandler polar motion can be studied based on long-term observation time series of latitude at a single
observatory, even if these observation records have gaps. We were the first to study the changes in the Chandler wobble for
that long time series of variations in the Pulkovo latitude with the help of different methods. The long observation record
and the methods of analysis of nonstationary time series had allowed us to identify two similar structures, both well apparent
during the periods of 1845–1925 and 1925–2005 in the time variations of phase and amplitude. The presence of this structure
indicates that low-frequency regularities may be present in the Chandler polar motion, and one of the manifestations of this
may be the well known feature in the region of 1925. The superimposed epoch method was used to estimate the period of variations
in the amplitude with a simultaneous change of phase of this oscillation, which was found to be 80 years. In addition, advantages
of singular spectral analysis for studying the long-period time series with involved structure are demonstrated. 相似文献
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J. T. Hooten K. G. Strassmeier D. S. Hall W. S. Barksdale Jr. A. Bertoglio S. Cortesi G. Cutispoto S. Engelbrektson M. Ganis J. M. Gómez R. Casas C. Gallart E. Jariod Y. Ito F. J. Melillo O. Ohshima R. S. Poole T. A. McLaughlin H. D. Powell R. M. Nix J. Soder R. Wasson 《Astrophysics and Space Science》1989,155(1):45-51
DifferentialUBV(RI)
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andUBVRI photometry of the RS CVn binary EI Eridani obtained during December 1987 and January 1988 at fourteen different observatories is presented. A combined visual bandpass light curve, corrected for systematic errors of different observatories, utilizes the photometric period of 1.945 days to produce useful results. Analysis shows the visual light curve to have twin maxima, separated by about 0.4 phase, and a full amplitude of approximately 0.06 mag for the period of observation, a smaller amplitude than reported in the past. The decrease in amplitude may be due to a decrease or homogenization of spot coverage. To fit the asymmetrical light curve, a starspot model would have to employ at least two spotted regions separated in longitude. 相似文献
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随着人类空间活动的急剧增加,同步轨道资源已变得十分稀缺。为此人们采用了多星共位技术,来充分挖掘同步轨道资源。多星共位中,由于卫星存在位置漂移的情况,安全问题成为维护卫星正常工作必须考虑的问题之一。考虑到同步卫星的轨道特性,常采用三程测距的方式对卫星进行测轨,而且需要较长时间的测轨弧段。连线干涉测量可以获得高精度的差分相位时延,这对卫星在垂直视线方向上构成了很强的约束。给出了连线干涉测量系统设计及测量数据处理方法,并对测量中的关键技术与设备特性、测量数据精度进行了初步分析。 相似文献
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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