Evolution of Galaxies and Observational Cosmology

将探测和选择效应纳入理论框架，对暗星系的数量和红移分布进行了宇宙学预测。研究表明，在给定视星等下，星系的探测率很大程度上取决于探测标准和星等测量算法，并且在最近的星系调查中，大量具有高红移的微弱星系可能仍未被探测到。通过使用当前的星系亮度演化模型，假设星系在数量或气候上不演化，将预测结果与未校正的b_jr_fik波段达到B_J = 27mag或等效深度的星系计数数据以及B_J = 23mag的Durham红移分布直接进行比较。结果表明，一个平坦的、低密度的、具有非零宇宙学常数的OMEGA_O - 0.1宇宙可以解释所有的数据，而一个平坦的、高密度的OMEGA_O = 1宇宙则与所有的数据存在明显的差异。星系在数量和/或直径上演化的假设是根据微弱的观测结果来检验的。与通常的预期相反，由星系合并驱动的数字演化不能调和在B_J = 27等处观测到的高计数和高密度的omega_o = 1宇宙，因为根据最近调查中采用的标准，许多高红移预合并不应该被计数。发现中心表面亮度与视星等的关系仅对星系的内在大小变化敏感，因此它被用作它们直径演变的探针。对预测和观测的关系的比较表明，大部分星系在相当大的年龄范围内经历了很少的直径演化。

Cosmological predictions of number count and redshift distribution of faint galaxies are made by incorporating detection and selection effects in the theoretical framework. It is shown that the detection rate for galaxies at given apparent magnitude strongly depends on the detection criterion and magnitude measurement algorithm, and that a large number of faint galaxies with high redshifts should remain undetected in recent galaxy surveys. By using a current model of galaxy luminosity evolution with the assumption that galaxies do not evolve in number or cliameter, the predictions are compared directly with the uncorrected B_JR_FIK-band galaxy count data reaching B_J = 27mag or the equivalent depth and also with the Durham redshift distribution to B_J = 23mag. It is concluded that a flat and low-density OMEGA_O - 0.1 universe with non-zero cosmological constant can account for all the data but a flat and high-density OMEGA_O = 1 universe shows a marked discrepancy with all the data. The hypothesis of galaxy evolution in number and/or diameter is tested against the faint observations. Contrary to usual expectations, a number evolution driven by galaxy mergers cannot reconcile the observed high count at B_J = 27mag and the high densityOMEGA_O = 1 universe because many high-redshift premergers should not be counted according to the criterion adopted in the recent surveys. The central surface brightness versus apparent magnitude relation is found to be sensitive solely to a change of intrinsic size of galaxies so that it is used as a probe of their diameter evolution. Comparison between the predicted and observed relations indicates that the bulk of galaxies have undergone very little diameter evolution over a considerable fraction of their age.