共查询到20条相似文献，搜索用时 93 毫秒
1.
利用γ射线脉冲星Ｇｅｍｉｎｇａ自旋及频率变化的稳定性，采用位相相关的方法分析了ＥＧＲＥＴ对脉冲星Ｇｅｍｉｎｇａ四次观测间隔较长的数据，得到较为准确的守时参数ｆ，位相相关的结果与更长数据段折叠搜索的结果较为接近，对于自旋和频率变化都较为稳定的γ射线脉冲星，位相相关分析方法可以作为提高脉冲星参数精度的有效方法。 相似文献
2.
Ｃｏｍｐｔｏｎγ射线望远镜ＣＯＭＰＴＥＬ／ＣＧＲＯ工作于０．７５－３０ＭｅＶ能区，本文应用直接解调方法分析ＣＧＲＯ＃１观测的ＣＯＭＰＴＥＬ数据，准确定出Ｃｒａｂγ射线源的位置，在１０－３０ＭｅＶ能区，分辨开最大似然法所不能完全分辨的Ｃｒａｂγ射线源和类星体ＰＫＳ０５２８＋１３４，得出优于传统成像方法所得的成像结果．应用直接成像方法处理γ射线脉冲星Ｇｅｍｉｎｇａ分位相数据，发现Ｇｅｍｉｎｇａ在１０－３０ＭｅＶ能区仍存在辐射，辐射集中在Ｇｅｍｉｎｇａ第一个峰的位相区域．结果表明，应用直接解调方法对Ｃｏｍｐｔｏｎ望远镜数据作成像分析是完全可行的 相似文献
3.
通过比较不同观测中Ｇｅｍｉｎｇａ脉冲星的γ射线绝对位相，测量出了不同时间Ｇｅｍｉｎｇａ的位置。这些位置表明Ｇｅｍｉｎｇａ自行的赤经分量为０．２２６±０．０３弧秒／年，与它的一个最可能的光学对应体Ｇ″的自行相一致，从而独立地确定了Ｇ″与Ｇｅｍｉｎｇａ之间的对应关系。 相似文献
4.
通过比较不同观测中Ｇｅｍｉｎｇａ脉冲星的γ射线绝对位相，测量出了不同时间Ｇｅｍｉｎｇａ的位置。这些位置表明Ｇｅｍｉｎｇａ自行的赤经分量为０．２２６±０．０３弧秒／年，与它的一个最可能的光学对应体Ｇ″的自行相一致，从而独立地确定了Ｇ″与Ｇｅｍｉｎｇａ之间的对应关系。 相似文献
5.
脉冲星Geminga MeV脉冲辐射证据 总被引：1，自引：0，他引：1
利用直接解调方法分析ＣＯＭＰＴＥＬ ＶＰ１数据,得到了脉冲星Ｇｅｍｉｎｇａ １０－３０ＭｅＶ脉冲辐射存在的证据;全位相及分位相成像均得到了Ｇｅｍｉｎｇａ。分位相成像结果显示,江变曲线的峰值位于ｐｕｌｓｅ１附近,而闰相区域只能给出上限。由于成 像分析不存在的选择效应,该成像结果表明,Ｇｅｍｉｎｇａ在ＭｅＶ能区仍存在脉冲辐射,虽然Ｇｅｍｉｎｇａ的弱ＭｅＶ辐射使得很难就ＶＰ１数据作时间分析,但仍得到了一 相似文献
6.
最近，一个困扰人们达十几年之久的γ射线源Ｇｅｍｉｎｇａ被证认为Ｘ、γ射线脉冲星，其光学对应体也被确定为一颗光谱偏蓝的２５等星。对Ｇｅｍｉｎｇａ脉冲星的确证说明存在着一类没有射电辐射的脉冲单星。 相似文献
7.
王仲翔 《中国天文和天体物理学报》1998,(1)
应用Ｕｓｏｖ和Ｍｅｌｒｏｓｅγ射线脉冲星的修正的极冠区内间隙模型,得出了γ射线脉冲星Ｇｅｍｉｎｇａ为什么没有射电脉冲辐射或射电脉冲辐射很弱的一种可能解释．同时,也可看出,中子星表面的多极场有着重要的作用． 相似文献
8.
应用Ｕｓｏｖ和Ｍｅｌｒｏｓｅγ射线脉冲星的修正的极冠区内间隙模型,得到了γ射线脉冲星Ｇｅｍｉｎｇａ为什么没射电脉冲辐射或射电脉冲辐射很弱的一种可能解释,同时,也可看出,中子星表面的多极场有着重要的作用。 相似文献
9.
本文分析γ射线脉冲星最近的观测数据，研究各波段辐射位相的一些关联，它们对于揭示γ射线脉冲星的辐射机制可能有重要的意义， 相似文献
10.
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
11.
VLBI (Very Long Baseline Interferometry)技术观测卫星需要对干涉测量数据进行相关和后处理,通过相关、时延校准、条纹搜索,最终得到卫星的基线几何时延.基于天文开源软件建立起一套卫星干涉测量数据处理系统.该系统可工作在实时和事后两种状态,实现相关、中性大气、电离层、钟模型以及仪器硬件的时延校准、条纹搜索、生成基线时延和时延率序列.使用该系统处理北斗GEO (Geosynchronous Earth Orbit)卫星的干涉测量试验数据,得到了精度在1–2 ns量级的卫星基线时延序列. 相似文献
12.
自适应光学技术应用于激光测月中大气波前倾斜量的探测与计算 总被引：2，自引：0，他引：2
针对云南天文台1.2米望远镜在激光测月中回波光子数太少的问题，将大气湍流效应考虑到激光测月中，研究了互相关和绝对差分两种跟踪算法的原理，并编写了算法程序，利用太阳数据验证了程序的正确性,给出了根据所采集的月面感兴趣区域的图像数据，用不同方法在不同条件下处理所得的大气波前整体倾斜信号，比较了算法的优劣。 相似文献
13.
K-line observations of enhanced network taken with the NASA/SPO Multichannel Spectrometer on 28 September 1975 in support of OSO-8 are discussed. The data show a correlation between core brightness and asymmetry for spatial scans which cross enhanced network boundaries. The implications of this result concerning mass flow in and near supergranule boundaries are discussed. 相似文献
14.
It is shown that the autocorrelation function of a telescope diffraction-limited image is closely approximated by a subtraction of the mean cross correlation of pairs of speckle photographs from the mean autocorrelation of the same set of data. This fact is used to derive the angular diameter of the asteroid Vesta from a series of speckle interferometry data. The resultant apparent angular diameter of 0″.40 ± 0″.04 corresponds to an absolute diameter of 513 ± 51 km. 相似文献
15.
The common observation that where photospheric magnetic fields are strong, the overlying corona is bright is examined quantitatively. White light coronal brightness is employed because it is independent of coronal temperature and is directly related to coronal electron density. Brightness data for the inner corona on 7 March, 1970, taken from isodensitometer traces having a resolution of 10 arc sec, are utilized. The data were obtained from photographs which exhibit distinct chromospheric features 5 arc sec or smaller. These data are quantitatively compared, using cross correlation and scatter plot techniques, with the corresponding photospheric magnetic field data provided by Kitt Peak National Observatory. Cross correlation coefficients are computed between latitudes ±55° at specified heights. In general, a statistically significant positive correlation is found. The correlation decreases with height in the corona. However, a range of values in several parameters remains to be investigated so the physical significance of the presently observed correlation is not yet entirely clear. We expect that refinement of our input parameters will produce a more sensitive correlation and lead to an expression for the relationship of electron density to photospheric magnetic field strength.NAS/NRC Research Associate. 相似文献
16.
《Chinese Astronomy and Astrophysics》2005,29(1):104-112
For dealing with the problem of too few photons in the return wave in lunar laser ranging, the effect of the atmospheric turbulence is studied. The principles of the two tracking algorithms, cross correlation and absolute difference are studied and programs are written, which are tested with solar data. Collected image data of the interested area on the lunar disc are given. The integrated tilt signals of the atmospheric wave front obtained are treated by different methods under different conditions and the algorithms are compared as to their effectiveness. 相似文献
17.
There is a correlation between Martian thermal inertia and radar cross section data centered on +22° latitude. The correlation is strongest with 70-cm radar, except between longitudes 10 and 90° where there is a slight anticorrelation, and gets progressively weaker at 12.5- and 3.8-cm wavelengths, respectively. A correlation is expected because of the dependence of both properties on density, but an increase in the average particle size of the surface with increasing dielectric constant is also required in order to explain the data. This may take the form of an increased number of small rocks. The anticorrelation may result from either the effects of atmospheric dust on the surface temperature or from the effects on radar of local variations in large-scale roughness or scattering by rocks. The relative behavior between the wavelengths can be understood in terms of appropriately sized rocks which act as radar scatterers. The trend of the correlation agrees with the dichotomy of the planet into two types of terrain, as noted in other remote-sensing data, and is consistent with an erosional versus depositional surface nature. Variations in the surface dielectric constant, inferred from the 3.8-cm radar data, can explain discrepancies between 2.8-cm radio emission observations and a simple model based on the global distribution of thermal inertia and albedo. 相似文献
18.
CygX—1硬态高能光子的时延 总被引：1，自引：1，他引：0
硬X射线和软射线光子的时延时研究主能辐射的一个重要方面，傅里叶交叉谱常常被用于教育处硬软光子之间的时延，但是交叉说示能在高于30Hz的傅里叶频率上从CygX-1测量到有统计意义的快速光变，由李惕培在时域上发展的交叉相关函方法能有效测量不同时间尺度上的时延，利用此交叉相关分析方法，讨论了不同观测时期CygX-1硬态高能光子时延 的性质，分析结果表明，CygX-1硬态在短的尺度（＜0．1秒）上存存在有意义的时间延迟，并将短时间尺度上的观测结果和各种CygX-1硬态模型进行了比较讨论。 相似文献
19.
Mofazzal H. Khondekar Dipendra N. Ghosh Koushik Ghosh Anup Kumar Bhattacharya 《Astrophysics and Space Science》2012,342(2):287-301
In the present work an attempt has been made to investigate statistical association between solar neutrino flux data (both D2O and Salt data) collected from Sudbury Neutrino Observatory and solar irradiance data detected by Earth Radiation Budget Satellite. To serve the present purpose we have used the Multifractal Detrended Cross Correlation Analysis (MF-DCCA) based on Detrended Fluctuation Analysis (MF-X-DFA) method and the Detrending Moving Average Analysis (MF-X-DMA) which explores the long term power-law cross correlations between above two pairs of data sets. Investigation also has been made to find the frequency and time dependent local phase relationship in each pair of data sets using continuous wavelet transform (CWT) based Semblance Analysis. The Semblance Analysis reveals that there exists positive phase correlation as well as negative phase correlation between solar irradiance and D2O data at different time sub-intervals. This type of mixed phase correlation is also experienced between solar irradiance and Salt data at different time sub-intervals. The causal relationship between the D2O and the solar irradiance time series and that between Salt and solar irradiance time series have been revealed using Singular Spectral Analysis (SSA). Calculations indicate that possibly the present solar neutrino flux data (both D2O and Salt data) is supportive to predict the solar irradiance data but may not the vice versa which in turn suggests that the variability of nuclear energy generation process inside the Sun may influence the solar activity. 相似文献
20.
对南银极区的亮星系样本和类星体候选者样本进行了两点交叉相关函数分析,最邻近间距分析和Kolmogorov-Smirnov检验;结果表明这两个样本之间不存在显著性相关。 相似文献