We present a new model to describe the galaxy-dark matter connection across cosmic time, which unlike the popular subhalo abundance-matching technique is self-consistent in that it takes account of the facts that (1) subhalos are accreted at different times and (2) the properties of satellite galaxies may evolve after accretion. Using observations of galaxy stellar mass functions (SMFs) out to z ~ 4, the conditional SMF at z ~ 0.1 obtained from Sloan Digital Sky Survey galaxy group catalogs, and the two-point correlation function (2PCF) of galaxies at z ~ 0.1 as a function of stellar mass, we constrain the relation between galaxies and dark matter halos over the entire cosmic history from z ~ 4 to the present. This relation is then used to predict the median assembly histories of different stellar mass components within dark matter halos (central galaxies, satellite galaxies, and halo stars). We also make predictions for the 2PCFs of high-z galaxies as function of stellar mass. Our main findings are the following: (1) Our model reasonably fits all data within the observational uncertainties, indicating that the ΛCDM concordance cosmology is consistent with a wide variety of data regarding the galaxy population across cosmic time. (2) At low-z, the stellar mass of central galaxies increases with halo mass as M 0.3 and M 4.0 at the massive and low-mass ends, respectively. The ratio M *, c /M reveals a maximum of ~0.03 at a halo mass M ~ 1011.8 h –1 M ☉, much lower than the universal baryon fraction (~0.17). At higher redshifts the maximum in M *, c /M remains close to ~0.03, but shifts to higher halo mass. (3) The inferred timescale for the disruption of satellite galaxies is about the same as the dynamical friction timescale of their subhalos. (4) The stellar mass assembly history of central galaxies is completely decoupled from the assembly history of its host halo; the ratio M *, c /M initially increases rapidly with time until the halo mass reaches ~1012 h –1 M ☉, at which point M *, c /M ~ 0.03. Once M 1012 h –1 M ☉, there is little growth in M *, c , causing the ratio M *, c /M to decline. In Milky Way (MW)-sized halos more than half of the central stellar mass is assembled at z 0.5. (5) In low-mass halos, the accretion of satellite galaxies contributes little to the formation of their central galaxies, indicating that most of their stars must have formed in situ. In massive halos more than half of the stellar mass of the central galaxy has to be formed in situ, and the accretion of satellites can only become significant at z 2. (6) The total mass in halo stars is more than twice that of the central galaxy in massive halos, but less than 10% of M *, c in MW-sized halos. (7) The 2PCFs of galaxies on small scales hold important information regarding the evolution of satellite galaxies, which at high-z is predicted to be much steeper than at low-z, especially for more massive galaxies. We discuss various implications of our findings regarding the formation and evolution of galaxies in a ΛCDM cosmology.
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机译：我们提出了一个新模型来描述跨宇宙时间的星系与暗物质的联系，这与流行的亚晕丰度匹配技术不同，它是自洽的，因为它考虑到以下事实：（1）亚晕在不同的时间积聚，并且（ 2）卫星星系的性质可能在吸积后发生变化。使用观测到z〜4的星系恒星质量函数（SMF），从斯隆数字天空测量星系组目录获得z〜0.1的条件SMF，以及z〜0.1的星系的两点相关函数（2PCF）为作为恒星质量的函数，我们限制了从z〜4到现在的整个宇宙历史中的星系与暗物质晕之间的关系。然后，可以使用这种关系来预测暗物质晕（中央星系，卫星星系和晕星）中不同恒星质量分量的中值组装历史。我们还预测了高z星系的2PCFs作为恒星质量的函数。我们的主要发现如下：（1）我们的模型合理地拟合了观测不确定性内的所有数据，这表明ΛCDM一致性宇宙学与跨宇宙时间的众多银河系数据相一致。 （2）在低z值时，中央星系的恒星质量随晕质量而增加，分别为质量端和低质量端的M 0.3和M 4.0。 M *，c / M之比在晕质量M〜1011.8 h –1 M at处显示最大值〜0.03，远低于通用重子分数（〜0.17）。在较高的红移下，M *的最大值c / M保持接近〜0.03，但移向较高的晕圈质量。 （3）推断出的卫星星系破裂的时间尺度与其亚晕的动摩擦时间尺度大致相同。 （4）中央星系的恒星质量组装史与它的主晕的组装史完全脱节;比率M *，c / M最初随时间快速增加，直到晕圈质量达到〜1012 h –1 M☉，此时M *，c / M〜0.03。一旦M 1012 h –1 M☉，M *，c几乎没有增长，导致比率M *，c / M下降。在银河系（MW）大小的光环中，超过一半的中央恒星质量以z 0.5组装。 （5）在低质量晕圈中，卫星星系的积聚对其中央星系的形成几乎没有贡献，这表明它们的大多数恒星一定是原位形成的。在巨大的晕圈中，中央星系的恒星质量的一半以上必须原位形成，而卫星的积聚只能在z 2时变得很重要。（6）晕圈恒星的总质量是恒星质量的两倍以上。大块光环中的中央星系，但兆瓦级光环中M *，c的比例不到10％。 （7）小规模星系的2PCF拥有有关卫星星系演化的重要信息，据预测，在高z时，它比低z时陡得多，特别是对于较大质量的星系。我们讨论关于ΛCDM宇宙学中星系形成和演化的发现的各种含义。
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