论文标题
$ z> $ 7的太阳金属银河系？可能检测[n ii] 122 $μ$ m和[o iii] 52 $μ$ m线
A solar metallicity galaxy at $z >$ 7? Possible detection of the [N II] 122 $μ$m and [O III] 52 $μ$m lines
论文作者
论文摘要
我们介绍了[n ii] 122 $μ$ m和[O III] 52 $μ$ m线的首次检测，用于重新离子 - 期间星系。基于这些行和以前的[C II] 158 $μ$ m和[O III] 88 $μ$ m的测量，使用两个不同的辐射转移模型的星际介质，我们估计电子密度的上限$ \ lyssim $ \ lyssim $ 500 cm $ $^{ - 3} $ 500 cm $^{ - 3} $ sim-phase $ z__ $ z_ $ 0. \ \ \ \ \ \ odoot \ odot \ odot odot。 A1689-ZD1，重力透镜，尘土飞扬的星系为$ z $ = 7.133。到目前为止，在$ z \ gtrsim $ 6的星系星际介质中，其他金属性的其他测量值或指标通常比此低的数量级。尽管恒星质量可能存在明显的灰尘遮挡，但异常高的金属性使A1689-ZD1与基本的金属关系不一致，尽管可能部分地解决了不一致的情况。鉴于太阳金属性，灰尘与金属比的比例低于预期的一个因素，这暗示了超过$ z \ sim $ 7的星系可能具有较低的灰尘形成效率。最后，与氧相比，被推断的氮富集在其上取决于金属性测量，这表明系统中的恒星形成大于大约250 MYR，将该星系的起点推向$ z> $ 10。
We present the first detection of the [N II] 122 $μ$m and [O III] 52 $μ$m lines for a reionisation-epoch galaxy. Based on these lines and previous [C II] 158 $μ$m and [O III] 88 $μ$m measurements, using two different radiative transfer models of the interstellar medium, we estimate an upper limit on electron density of $\lesssim$ 500 cm$^{-3}$ and a gas-phase metallicity $Z/Z_\odot \sim 1.1 \pm 0.2$ for A1689-zD1, a gravitationally-lensed, dusty galaxy at $z$ = 7.133. Other measurements or indicators of metallicity so far in galaxy interstellar media at $z \gtrsim$ 6 are typically an order of magnitude lower than this. The unusually high metallicity makes A1689-zD1 inconsistent with the fundamental metallicity relation, although there is likely significant dust obscuration of the stellar mass, which may partly resolve the inconsistency. Given a solar metallicity, the dust-to-metals ratio is a factor of several lower than expected, hinting that galaxies beyond $z \sim$ 7 may have lower dust formation efficiency. Finally, the inferred nitrogen enrichment compared to oxygen, on which the metallicity measurement depends, indicates that star-formation in the system is older than about 250 Myr, pushing the beginnings of this galaxy to $z >$ 10.
