论文标题
皇后。 V.超过12+log（O/h）= 〜6.9-8.9的金属诊断，由本地星系普查建立：准备JWST光谱法
EMPRESS. V. Metallicity Diagnostics of Galaxies over 12+log(O/H)=~6.9-8.9 Established by a Local Galaxy Census: Preparing for JWST Spectroscopy
论文作者
论文摘要
我们介绍了通过本地SDSS星系和最大金属贫困星系（EMPG）的最大汇编（包括Subaru Empress调查确定的新EMPG）建立的光学线气金属性诊断。总共包括103个EMPG，涵盖了一个较大的参数空间（MI = -19至-7）和H-Beta等效宽度（10-600 ANG），即恒星质量和恒星形成率的宽范围。使用这些星系的直接方法的可靠金属度测量值，我们在12+log（O/H）= 〜6.9-8.9范围内得出了强光学比率与气相金属性之间的关系，对应于0.02-2太阳能金属Zsun。我们确认R23-Index（[OIII]+[OII]）/H-Beta是最准确的金属性指标，金属不确定性在各种流行的金属性指标中的金属不确定性为0.14 DEX。其他金属性指标显示在金属贫困范围内（<0.1 ZSUN）。我们的阴云光电离建模可以解释，与R23索引不同，其他金属性指标不会使用单一和双电离线的总和，并且不能同时追踪低电离气体和高电离气体。我们发现，如果人们使用与电离状态紧密相关的H-Beta等效宽度测量值，则金属度指标的准确性会显着提高。 In this work, we also present the relation of physical properties with UV-continuum slope beta and ionization production rate xi_ion derived with GALEX data for the EMPGs, and provide local anchors of galaxy properties together with the optical-line metallicity indicators that are available in the form of ASCII table and useful for forthcoming JWST spectroscopic studies.
We present optical-line gas metallicity diagnostics established by the combination of local SDSS galaxies and the largest compilation of extremely metal-poor galaxies (EMPGs) including new EMPGs identified by the Subaru EMPRESS survey. A total of 103 EMPGs are included that cover a large parameter space of magnitude (Mi=-19 to -7) and H-beta equivalent width (10-600 Ang), i.e., wide ranges of stellar mass and star-formation rate. Using reliable metallicity measurements of the direct method for these galaxies, we derive the relationships between strong optical-line ratios and gas-phase metallicity over the range of 12+log(O/H)=~6.9-8.9 corresponding to 0.02-2 solar metallicity Zsun. We confirm that R23-index, ([OIII]+[OII])/H-beta, is the most accurate metallicity indicator with the metallicity uncertainty of 0.14 dex over the range among various popular metallicity indicators. The other metallicity indicators show large scatters in the metal-poor range (<0.1 Zsun). It is explained by our CLOUDY photoionization modeling that, unlike R23-index, the other metallicity indicators do not use a sum of singly and doubly ionized lines and cannot trace both low and high ionization gas. We find that the accuracy of the metallicity indicators is significantly improved, if one uses H-beta equivalent width measurements that tightly correlate with ionization states. In this work, we also present the relation of physical properties with UV-continuum slope beta and ionization production rate xi_ion derived with GALEX data for the EMPGs, and provide local anchors of galaxy properties together with the optical-line metallicity indicators that are available in the form of ASCII table and useful for forthcoming JWST spectroscopic studies.
