Metallicity has followed local gravitational potential of galaxies since z = 3
Metallicity has followed local gravitational potential of galaxies since z = 3
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自 z = 3 以来，金属丰度遵循星系的局部引力势
DOI：
10.1093/mnras/staa128
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发表时间：
2019
影响因子：
4.8
通讯作者：
L. Christensen
中科院分区：
文献类型：
--
作者：
P. Møller;L. Christensen
邻近星系的恒星质量（M*）和金属丰度(Z)之间的MZ关系被描述为既是全局性质也是局部性质，即在亚星系尺度上也是有效的。在这里，我们证明，自从Z = 3以来，随着引力势，Z仍然是一个局部性质。在吸收中，MZ关系已经得到了很好的研究，并且在z = 5.1处已经存在。最近对伽马射线暴星系的吸收研究揭示了与阻尼Lyα (DLA)星系的密切匹配，由于它们的影响参数截然不同，这令人惊讶，并导致作者提出局部金属丰度遵循局部引力势。在本文中，我们对这一假设进行了观测检验。该试验实质上形成了一个预测，即星系晕中吸收气体的速度色散，通过中心速度色散归一化，必须遵循一个陡峭的对数尺度斜率- 0.015 dex $\rm kpc^{-1}$作为冲击参数的函数，至少达到20-30 kpc。然后，我们编制了一个档案数据和基于文献的星系样本，这些样本在发射和吸收方面都适合于测试，并发现目前的数据在40 - 60kpc的范围内证实了这一假设。此外，我们还表明zem和zabs之间的速度偏移分布有利于DLA系统由沿整个光晕路径分布的单个子云组成的模型，而不利于它们是具有大量运动和内部子结构的单个云的模型。
The MZ relation between stellar mass (M*) and metallicity (Z) of nearby galaxies has been described as both a global and local property, i.e. valid also on sub-galaxy scales. Here, we show that Z has remained a local property, following the gravitational potential, since z = 3. In absorption, the MZ relation has been well studied, and was in place already at z = 5.1. A recent absorption study of gamma-ray burst galaxies revealed a close match to damped Lyα (DLA) galaxies, surprising due to their vastly different impact parameters and leading the authors to suggest that local metallicity follows the local gravitational potential. In this paper, we formulate an observational test of this hypothesis. The test, in essence, forms a prediction that the velocity dispersion of the absorbing gas in galaxy haloes, normalized by the central velocity dispersion, must follow a steep log scale slope of −0.015 dex $\rm kpc^{-1}$ as a function of impact parameter out to at least 20–30 kpc. We then compile an archival data and literature-based sample of galaxies seen in both emission and absorption suitable for the test, and find that current data confirm the hypothesis out to 40–60 kpc. In addition, we show that the distribution of the velocity offsets between zem and zabs favours a model where DLA systems are composed of individual sub-clouds distributed along the entire path through the halo, and disfavours a model where they are one single cloud with a bulk motion and internal sub-structure.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.