On the galaxy stellar mass function, the mass-metallicity relation, and the implied baryonic mass function
On the galaxy stellar mass function, the mass-metallicity relation, and the implied baryonic mass function
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DOI：
10.1111/j.1365-2966.2008.13348.x
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发表时间：
2008-04
影响因子：
4.8
通讯作者：
I. Baldry;K. Glazebrook;S. Driver
中科院分区：
文献类型：
--
作者：
I. Baldry;K. Glazebrook;S. Driver
已发表的场星系恒星质量函数(GSMF)的比较表明，宇宙恒星的质量密度在重子密度的4%-8%的范围内(假设b=0.045)。即使假设一个合理的普适恒星初始质量函数，杜斯特修正和潜在恒星质量光比仍然存在显著的不确定性来源。我们使用来自斯隆数字巡天的49968个星系的纽约大学增值星系目录样本和对恒星质量的各种估计来确定z<；0.05GSMF。GSMF显示了低质量回升的明显证据，并配备了具有�2≃−1.6的双谢克特功能。在质量低于∼108.5M⊙时，由于缺少L低表面亮度星系，GSMF可能是显著不完整的。对恒星质量-金属丰度关系的一种解释是，它主要是由L低质量星系中转化为恒星的较低比例的可用重子造成的。利用这个原理，我们确定了重子质量和恒星质量之间的一个简单关系，并给出了一个“隐含的重子质量函数”。该函数的端斜率为�2≃−1.9。因此，我们发现有证据表明，星系y质量函数的低质量端的斜率可能与晕质量函数一样陡峭。我们说明了晕重子质量函数→星系重子质量函数→GSMF之间的关系。这说明在重子质量∼10 11M⊙对应最小反馈效应的情况下，星系形成的峰值效率是必需的。重子落入效率Cy可能在较低质量时已趋于平稳。
A comparison between published field galaxy stellar mass fun ctions (GSMFs) shows that the cosmic stellar mass density is in the range 4‐8 per cent of the baryon density (assuming b = 0.045). There remain significant sources of uncertainty for the du st correction and underlying stellar mass-to-light ratio even assuming a reaso nable universal stellar initial mass function. We determine the z < 0.05 GSMF using the New York University ‐ Value-Added Galaxy Catalog sample of 49968 galaxies derived from the Sloan Digital Sky Survey and various estimates of stellar mass. The GSMF shows clear evidence for a low-mass upturn and is fitted with a double Schechter function that has �2 ≃ −1.6. At masses below ∼ 10 8.5 M⊙, the GSMF may be significantly incomplete because of missing l ow surface-brightness galaxies. One interpretation of the stellar mass-metallicity re lation is that it is primarily caused by a lower fraction of available baryons converted to stars in l ow-mass galaxies. Using this principal, we determine a simple relationship between baryonic mass and stellar mass and present an ‘implied baryonic mass function’. This function has a fai nt-end slope, �2 ≃ −1.9. Thus, we find evidence that the slope of the low-mass end of the galax y mass function could plausibly be as steep as the halo mass function. We illustrate the relationship between halo baryonic mass function → galaxy baryonic mass function → GSMF. This demonstrates the requirement for peak galaxy formation efficiency at baryonic masses ∼ 10 11 M⊙ corresponding to a minimum in feedback effects. The baryonic-infall efficien cy may have levelled off at lower masses.