Factors for Incompleteness of QSO's Sample and V/V<SUB>max</SUB> Analysis

Liu Zu-wei; Zhang He-qi

doi:10.11728/cjss1985.01.001

Volume 5 Issue 1

Jan. 1985

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Liu Zu-wei, Zhang He-qi. Factors for Incompleteness of QSO's Sample and V/Vmax Analysis[J]. Chinese Journal of Space Science, 1985, 5(1): 1-10. doi: 10.11728/cjss1985.01.001

Citation:

Liu Zu-wei, Zhang He-qi. Factors for Incompleteness of QSO's Sample and V/V_max Analysis[J]. Chinese Journal of Space Science, 1985, 5(1): 1-10. doi: 10.11728/cjss1985.01.001

Liu Zu-wei, Zhang He-qi. Factors for Incompleteness of QSO's Sample and V/Vmax Analysis[J]. Chinese Journal of Space Science, 1985, 5(1): 1-10. doi: 10.11728/cjss1985.01.001

Citation:

Liu Zu-wei, Zhang He-qi. Factors for Incompleteness of QSO's Sample and V/V_max Analysis[J]. Chinese Journal of Space Science, 1985, 5(1): 1-10. doi: 10.11728/cjss1985.01.001

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Factors for Incompleteness of QSO's Sample and V/V_max Analysis

doi: 10.11728/cjss1985.01.001 cstr: 32142.14.cjss1985.01.001

Purple Mountain Observatory, Academia Sinica

Received Date: 1984-02-22
Rev Recd Date: 1900-01-01
Publish Date: 1985-01-24

Abstract

Abstract

The V/V_max analysis is a powerful method to study quasar density distribution and luminosity evlution, but the observed sample N(>l_min, n) can not be regarded as complete when used to investigate the density law in the range of zN and intrinsic luminosities of different sources in the sample are different, so that, to a certain extent, the results of usual procedure are not reliable enough. We present an idea that the quasar L-z curve, from which the deviation of actual sources obeys a certain probability distribution, can be obtained by statistics, and then, the incompleteness factor K(z|l_min)for each source can be given. In this paper we adopt the regression iteration procedure with censored data, assuming deviation of quasar sources from L-z curve follows normal distribution approximately, and analyze the SCRand 4Csamples. On 90% confidence level the space density distribution of quasars is relative to q₀ For q₀=0, quarsar are close to homogeneous distribution. For q₀=1/2, the quasar number increases slightly with the increase of redshift. Only for q₀=1, quasars have a strong cosmological evolution. The value of 2 to 6 of the parameter r of density law in the case q₀=1 is smaller than that of 10 to 12 derived by previous V/Vmax test, so it is relatively more consistent with the theoretical model to explain quasar form and density evolution in virtue of low density of intergalactic medium. The 3CR sources detected in X-ray are also analyzed, which shows our revised method with incompleteness factors can characterize the sample in different wave band regions.