The distribution of stellar mass in the low‐redshift Universe
The distribution of stellar mass in the low‐redshift Universe
复制标题
DOI：
10.1111/j.1365-2966.2009.15268.x
复制
发表时间：
2009-01
影响因子：
4.8
通讯作者：
Cheng Li;S. White
中科院分区：
文献类型：
--
作者：
Cheng Li;S. White
我们使用了一个完整的和统一的样本，近50万个星系从斯隆数字巡天来表征恒星质量的分布在低红移宇宙。星系丰度在恒星质量的近四个数量级上得到了很好的确定，并且合理但不完全符合特征恒星质量m（*）= 6.7 x 1010 M（圆点）和暗端斜率α =-1.155的谢克特函数。对于一个标准的宇宙学和一个标准的恒星初始质量函数，在低红移宇宙中只有3.5%的重子被锁定在恒星中。在r（p）< 30 h-1 Mpc时，得到了恒星质量投影自相关函数的精确值.在10 h-1 kpc < r（p）< 10 h-1 Mpc的范围内，它非常好地用幂律表示。相应的三维自相关函数为xi*（r）=（r/6.1 h-1 Mpc）-1.84。相对于暗物质，恒星质量分布的偏差在大尺度上近似为常数，但当r（p）< 1 h-1 Mpc时，偏差会有5倍的变化。这种行为是近似的，但不完全复制的和谐λ冷暗物质宇宙学的星系形成的当前模型。详细的比较表明，波动幅度σ（8）类似于0.8是首选的千年模拟模型中采用的稍大的值，我们比较我们的数据。这种比较也表明，恒星质量自相关作为红移函数的观测可能为暗能量的性质提供了一个强有力的测试。
We use a complete and uniform sample of almost half a million galaxies from the Sloan Digital Sky Survey to characterize the distribution of stellar mass in the low-redshift Universe. Galaxy abundances are well determined over almost four orders of magnitude in stellar mass and are reasonably but not perfectly fit by a Schechter function with characteristic stellar mass m(*) = 6.7 x 1010 M(circle dot) and with faint-end slope alpha = -1.155. For a standard cosmology and a standard stellar initial mass function, only 3.5 per cent of the baryons in the low-redshift Universe are locked up in stars. The projected autocorrelation function of stellar mass is robustly and precisely determined for r(p) < 30 h-1 Mpc. Over the range 10 h-1 kpc < r(p) < 10 h-1 Mpc, it is extremely well represented by a power law. The corresponding three-dimensional autocorrelation function is xi*(r) = (r/6.1 h-1 Mpc)-1.84. Relative to the dark matter, the bias of the stellar mass distribution is approximately constant on large scales, but varies by a factor of 5 for r(p) < 1 h-1 Mpc. This behaviour is approximately but not perfectly reproduced by current models for galaxy formation in the concordance Lambda cold dark matter cosmology. Detailed comparison suggests that a fluctuation amplitude Sigma(8) similar to 0.8 is preferred to the somewhat larger value adopted in the Millennium Simulation models with which we compare our data. This comparison also suggests that observations of stellar mass autocorrelations as a function of redshift might provide a powerful test for the nature of Dark Energy.