New detections of Mn, Ti and Mg in damped Lyα systems: Toward reconciling the dust/nucleosynthesis degeneracy
New detections of Mn, Ti and Mg in damped Lyα systems: Toward reconciling the dust/nucleosynthesis degeneracy
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阻尼 Lyα 系统中锰、钛和镁的新检测：协调尘埃/核合成简并性
DOI：
10.1051/0004-6361:20020843
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发表时间：
2002
影响因子：
6.5
通讯作者：
S. D’odorico
中科院分区：
文献类型：
--
作者：
M. Dessauges;J. Prochaska;S. D’odorico
我们将 zabs= 1:7 2:5 之间红移的四个阻尼 Ly 系统 (DLA) 样本的新高分辨率 UVES-VLT 观测结果与现有的 HIRES-Keck 光谱相结合，对它们的物理条件和多达 15 种元素的丰度进行全面研究。在本文中，我们提出了 Mn、Ti 和 Mg 的丰度测量结果，这是文献中首次提出的这些红移测量结果。我们证实了在较低红移 DLA 中观察到的 Mn 相对于 Fe 的丰度不足，并且金属丰度下降的趋势与在银河系贫金属恒星中观察到的非常相似。 DLA 和银河系恒星的 Mn/Fe 比率之间的一致性表明 DLA 和银河系在恒星形成历史上有一些相似之处。然而，必须根据 DLA 中观察到的所有要素来谨慎解释和研究这些相似之处。我们从 Tiii 线静止> 3000 A 获得了 zabs 2 处 Ti 丰度的第一次测量和显着上限，并且我们讨论了如何使用这种高度贫化元素的相对丰度来明确证明 元素相对于 Fe 峰元素丰度的任何增强。除了文献中存在的单个 Mg 测量值之外，我们还提供了两个 DLA 的 Mg 丰度。与差值损耗预期的趋势相反，（Mg/Si，S）比率往往超过太阳。该效应处于测量误差的水平，但值得在更大的样本中进行研究，因为它可能暗示着一种特殊的核合成效应。
We have combined new high resolution UVES-VLT observations of a sample of four damped Ly systems (DLAs) at redshifts between zabs= 1:7 2:5 with the existing HIRES-Keck spectra to undertake a comprehensive study of their physical conditions and their abundances of up to 15 elements. In this paper, we present abundance measurements for Mn, Ti and Mg which are among the first presented in the literature at these redshifts. We confirm the underabundance of Mn with respect to Fe as observed in lower redshift DLAs and a trend with decreasing metallicity very similar to the one observed in Galactic metal-poor stars. This agreement between the Mn/Fe ratios in DLAs and in Galactic stars suggests that the DLAs and the Milky Way share some similarities in their star formation histories. However, these similarities must be cautiously interpreted and investigated in light of all of the elements observed in the DLAs. We have obtained a first measurement and a significant upper limit of the Ti abundance at zabs 2 from the Tiii lines atrest> 3000 A, and we discuss how the relative abundance of this highly depleted element can be used to prove unambiguously any enhancement of the abundance of the-elements relative to Fe-peak elements. We present the abundances of Mg for two DLAs in addition to the single Mg measurement existing in the literature. Contrary to the trend expected from dierential depletion, the (Mg/Si, S) ratios tend to be over-solar. The eect is at the level of the measurement errors, but worth investigating in a larger sample because it could be suggestive of a peculiar nucleosynthesis eect.