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991.
992.
We discuss the changes in the amplitude of the correlation function of quasar clustering with the redshift. Using the new Hewitt-Burbidge QSO catalogue, we find from a statistical analysis of the quasar pairs that the positive results of quasar clustering are mainly contributed by low-redshift quasars. There is an obvious change in the quasar distribution at z = 2. There is no clustering for z > 2. The difference in clustering is not due to any selection effect on the brightness. The evidence is that quasar clustering evolved with cosmological time. 相似文献
993.
西昆仑库地以南有一套变质变形较强的岩系,前人依照区域对比关系将其划为前寒武的古老基底。对西昆仑早期构造演化的论述均基于该观点,但没有提供确凿的同位素年代学证据。笔者通过野外观察、室内研究,确认库地以南的变质变形岩系是大型韧性推覆剪切作用的产物。通过对新生变质矿物角闪石和黑云母单矿物的40Ar/39Ar年龄分析,确定剪切变质年龄为426-451Ma,说明库地的变质变形岩系是形成于早古生代晚期的一条大型韧性剪切带,这对于解释西昆仑的早期构造演化具有重要意义。 相似文献
994.
The question of the association of quasars with galaxies is re-examined using 785 quasars at |b| 30, δ − 02°30′ in the new Hewitt and Burbidge Catalog (1980) and all galaxies in the “Uppsala General Catalogue of Galaxies” (Nilson, 1973). The results of the two-point cross-correlation function are presented and they show that there are on the average 0.153 ± 0.011 more galaxies within 10'.0 of a QSO than would be expected if the QSOs were distributed randomly. We find the marginal significance of the tendency for correlation between QSOs and galaxies to increase with increasing redshifts z or apparent magnitudes V. The nearest neighbor test has also been taken to analyse the same data as well as get further evidence for the apparent association between QSOs and galaxies. 相似文献
995.
We applied power spectral analysis to the redshift distribution of the quasars associated with low-redshift galaxies. Periodicity is confirmed at a level of confidence >99%, with a period of Δln(1+z) = 0.206. This result is exactly the same as previously found for different quasar samples. The periodicity is not caused by any selection effect in the emission lines. The two phenomena, the periodicity in the redhsift distribution and the association of quasars with low-redhsift galaxies can both be rather well explained by a multiply-connected model of the universe. 相似文献
996.
997.
Taking pulsars with long pulse nulling as forming a special group, we found that those with pronounced nulling are located on a line near and parallel to the radio cut-off in the 1gP — 1gP diagram. This in turn suggests a reason for the nulling. They are also shown to have smaller than average fields at the light cylinder and to have smaller than average rates of energy dissipation. 相似文献
998.
Yao-zhong Chu 《Chinese Astronomy and Astrophysics》1985,9(1):35-38
Using the time observations obtained by 8 instruments in the Chinese Joint System during the years 1966–1980, we analyse the Moon's zonal tidal effect. The results show that the effects of the Mf and Mm waves are obvious. From this, the parameters of the zonal tide are estimated and the weighted averages of the 8 instruments are respectively. 相似文献
999.
1000.
介绍瑞士ARL8680型X射线荧光光谱仪在更换高压发生器后出现的故障现象、原因及处理方法。 相似文献