The nitrogen and oxygen abundances in the neutral gas at high redshift
The nitrogen and oxygen abundances in the neutral gas at high redshift
复制标题
高红移下中性气体中氮和氧的丰度
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
R. Srianand
中科院分区：
文献类型：
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作者：
P. Petitjean;C. Ledoux;R. Srianand
目标。我们研究了高红移星系星际介质中氧和氮的丰度。方法.我们使用高分辨率和高信噪比的阻尼莱曼- α（DLA）系统的光谱检测沿着视线类星体，从不饱和金属吸收线获得强大的丰度测量。结果我们给出了16个高红移DLAs和强亚DLAs（log N（H I）> 19.5，2.4 z abs ± 0.10（-2.5 -1）和9个[N/O] <-1.15）的结果。在[N/O]对[O/H]的图中，[N/O] ~-0.9处可能存在一个松散的平台，低于贫金属矮星系中所谓的主平台（[N/O]在-0.57到-0.74之间）。在这个主要平台之上没有看到任何系统，而大多数系统都位于下面，分布很大。所有这一切都表明了一幅DLA经历连续恒星爆发的画面。在这样的插曲，[N/O]比急剧下降，因为快速释放的氧气的大质量恒星，而在两个爆发之间，氮释放的低和中等质量的恒星与延迟和[N/O]比增加。
Aims. We study the oxygen and nitrogen abundances in the interstellar medium of high-redshift galaxies. Methods. We use high resolution and high signal-to-noise ratio spectra of damped Lyman- α (DLA) systems detected along the line-of-sight to quasars to derive robust abundance measurements from unsaturated metal absorption lines. Results. We present results for a sample of 16 high-redshift DLAs and strong sub-DLAs (log N (H I) > 19.5, 2.4 z abs ± 0.10 for -2.5 -1 and nine systems have [N/O] < -1.15. In the diagram [N/O] versus [O/H], a loose plateau is possibly present at [N/O] ~ -0.9, which is below the so-called primary plateau as seen in local metal-poor dwarf galaxies ([N/O] in the range -0.57 to -0.74). No system is seen above this primary plateau whereas the majority of the systems lie well below with a large scatter. All this suggests a picture in which DLAs undergo successive star-bursts. During such an episode, the [N/O] ratio decreases sharply because of the rapid release of oxygen by massive stars, whereas inbetween two bursts, nitrogen is released by low and intermediate-mass stars with a delay and the [N/O] ratio increases.
DOI：
10.1051/0004-6361:20054328
发表时间：
2006-02
期刊：
arXiv: Astrophysics
影响因子：
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作者：
P. Erni;P. Richter;C. Ledoux;P. Petitjean
通讯作者：
P. Erni;P. Richter;C. Ledoux;P. Petitjean