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arXiv 2111.03074astro-ph.GA
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z>4时星际介质富集的加速

The ramp-up of interstellar medium enrichment at z>4

M. Franco, K. E. K. Coppin, J. E. Geach, C. Kobayashi, S. C. Chapman, C. Yang, E. González-Alfonso, J. S. Spilker, A. Cooray, M. J. Michałowski

摘要:

氟是原子核和恒星天体物理学中最有趣的元素之一。1992年首次测量了太阳以外的恒星的氟丰度,然后是少数几颗贫金属恒星,这些恒星可能在宇宙早期形成。氟的主要产生地点仍在争论之中,包括渐近巨星分支(AGB)星、核心坍缩超新星中的$ν$过程和沃尔夫-拉叶(WR)星。由于祖先恒星的质量和寿命的差异,对氟的高红移观测有助于限制大质量星系中氟产生的机制。在这里,我们报告的检测HF(S/N = 8)的吸收引力透镜尘埃恒星形成星系在红移z=4.4与$N_{\rm HF}$ / $N_{\rm{H_2}}$高达$\sim2\times10^{-9}$,表明一个非常快速的斜坡上的化学富集在这个高z星系。在z=4.4时,只有几个太阳质量的AGB星不太可能主导浓缩。相反,我们表明,WR星需要在这个时候产生所观察到的氟丰度,其他生产机制在以后的时间变得重要。因此,这些观测结果提供了一个深入了解的基本过程驱动的“斜坡”阶段的化学浓缩,同时快速恒星质量组装在一个年轻的大质量星系。

英文摘要:

Fluorine is one of the most interesting elements for nuclear and stellar astrophysics. Fluorine abundance was first measured for stars other than the Sun in 1992, then for a handful metal-poor stars, which are likely to have formed in the early Universe. The main production sites of fluorine are under debate and include asymptotic giant branch (AGB) stars, $ν$-process in core-collapse supernovae, and Wolf-Rayet (WR) stars. Due to the difference in the mass and lifetime of progenitor stars, high redshift observations of fluorine can help constrain the mechanism of fluorine production in massive galaxies. Here, we report the detection of HF (S/N = 8) in absorption in a gravitationally lensed dusty star-forming galaxy at redshift z=4.4 with $N_{\rm HF}$/$N_{\rm{H_2}}$ as high as $\sim2\times10^{-9}$, indicating a very quick ramp-up of the chemical enrichment in this high-z galaxy. At z=4.4, AGB stars of a few solar masses are very unlikely to dominate the enrichment. Instead, we show that WR stars are required to produce the observed fluorine abundance at this time, with other production mechanisms becoming important at later times. These observations therefore provide an insight into the underlying processes driving the `ramp-up' phase of chemical enrichment alongside rapid stellar mass assembly in a young massive galaxy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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