类星体L_α森林吸收线密度与发射红移的相关性

本文对16个高红移类星体的L_α森林吸收线密度N(z_(abs))统计分析的结果,表明它明显地依赖于类星体自身的发射红移z_(em)。这不仅表现在z(em)越大的类星体其全部L_α吸收线的平均数密度N(z_(abs))也越大;更重要的是,对于相同的吸收红移值z_(abs),而言,N(z_(abs))在统计意义上明显地随着类星体z_(em)的增大而增大。另一方面,本文也在“吸收体源自类星体抛射”的框架下作了统计,结果仍表明z_(em)对L_α森林吸收线密度有显著影响,但抛射速度却对被抛射体的数目无显著影响。最后,对所得的结果以及可能影响N(z_(abs))的若干因素作了讨论。

Correlation Between Lyman Alpha Absorption Line Density and the Emission Line Redshift of the QSO

This paper presents some results of the statistic study of the Lyman Alpha forest in the absorption line spectra of high redshift QSOs. The samples (Table 1) used for this work consist of the spectra of 16 objects which have been widely studied by various authors for the same topic. However, our statistics are somewhat different from the others in the sense that it is the emission lino redshift zem rather than the absorption line redshift zabs which shows correlation with the line density of the Lyman Alpha forest. The main results can be summarized as follows:1) The mean line density in the observed pure Lyman Alpha wavelength region is increased with the increasing of zem of the QSO;2) The mean line density in the same wavelength interval (therefore, having the same absorption line redshift) is increased with the increasing of zem of the QSO too.3) The two factor variation analysis with beta, the velocity of Lyman Alpha cloud relative to the QSO, and zem as two variables, shows that the Lymae Alpha absorption line density depends significantly on zem but not on beta at all.Some discussions are given to piont out that these results are difficult to be interpreted either by intervening or by ejecting hypothesis, and are unlikely due to the selection effects suggested by Carswell et al. Therefore, it is suggested here in order to make this statistics sound, even larger collection of uniform samples is extremely desired.