However , it is impossible for astronomers to see the even horizon directly due to the current technical limitation . therefore what scientists discovered so far is only an indirect evidence of the gravitational redshift or similar phenomenon caused by black holes . but those results undoubtedly become an important bridge for linking black hole theory with actual observation 虽然目前的观测技术尚未允许我们直接看到黑洞的视界，所以有关黑洞产生的重力红移或者类似的观测结果都不是决定性的，但这些结果无疑会成为连系黑洞理论和实际观测的重要桥梁。
Our test with mock samples shows furthermore that one can discriminate among such models already with currently available observational samples ( if the measurement error of the redshift is negligible ) which have a typical error of 80kms - 1 . the error will be reduced by a factor of 2 if the samples are increased four times . we also show that an errroneous assumption about the geometry of the universe and different infall models only slightly change the results 结果表明： ( 1 )若用现有的观测样本(特征误差为80kms ~ ( - 1 ) )我们已经可以限制星系形成模型，而如果样本容量增长到4倍，误差将减半； ( 2 )错误地假设宇宙几何和星系平均内落对结果只有微弱的影响。
