The Gas and Stellar Content of a Metal-poor Galaxy at z = 8.496 as Revealed by JWST and ALMA
The Gas and Stellar Content of a Metal-poor Galaxy at z = 8.496 as Revealed by JWST and ALMA
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DOI：
10.3847/2041-8213/acb2cf
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发表时间：
2022-12
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通讯作者：
K. Heintz;C. Giménez-Arteaga;S. Fujimoto;G. Brammer;D. Espada;S. Gillman;J. Gonz'alez-L'opez;T. Greve;Y. Harikane;B. Hatsukade;K. Knudsen;A. Koekemoer;K. Kohno;V. Kokorev;M. Lee;G. Magdis;E. Nelson;F. Rizzo;R. Sanders;D. Schaerer;A. Shapley;V. Strait;S. Toft;F. Valentino;A. V. D. Wel;A. Vijayan;D. Watson;F. Bauer;C. Christiansen;S. Wilson
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作者：
K. Heintz;C. Giménez-Arteaga;S. Fujimoto;G. Brammer;D. Espada;S. Gillman;J. Gonz'alez-L'opez;T. Greve;Y. Harikane;B. Hatsukade;K. Knudsen;A. Koekemoer;K. Kohno;V. Kokorev;M. Lee;G. Magdis;E. Nelson;F. Rizzo;R. Sanders;D. Schaerer;A. Shapley;V. Strait;S. Toft;F. Valentino;A. V. D. Wel;A. Vijayan;D. Watson;F. Bauer;C. Christiansen;S. Wilson
我们提出了一个联合分析的星系S 04590在z = 8.496的基础上获得的NIRSpec，NIRCam和NIRISS观测的早期释放观测计划的一部分，詹姆斯韦伯太空望远镜（JWST）和远红外[C ii] 158 μm发射线检测专用阿塔卡马大型毫米/亚毫米阵列（阿尔马）的观测。我们确定的光谱能量分布（SED）的建模和通过红移光学星云发射线检测与JWST/NIRSpec的S 04590的物理性质。最佳拟合的SED模型揭示了一个低质量（M = 107.2-108 M ⊙）星系，其低氧丰度为12+log（O/H）=7.16 - 0.12+0.10，来自强星云和极光发射线。假设[C ii]有效地追踪了星际介质，我们根据[C ii]的光度和空间范围估计星系的总气体质量为M气体=（8.0 ± 4.0）× 108 M。这产生了异常高的气体分数，f气体= M气体/（M气体+ M）<$90%，尽管仍然与低金属丰度的预期范围一致。我们进一步推导出星系的金属质量的基础上的气体质量和气相金属丰度，我们发现这是符合预期的金属生产II型超新星。最后，我们对z = 6的再电离时期星系的尘埃-气体（DTG）和尘埃-金属（DTM）比进行了第一次限制，显示出logDTG < −3.8和logDTM < −0.5的整体低质量比，尽管它们与已建立的标度关系一致，特别是与本地贫金属星系I Zwicky 18的标度关系一致。我们的分析突出了阿尔马和JWST在表征第一代星系的气体，金属和恒星含量之间的协同作用。
We present a joint analysis of the galaxy S04590 at z = 8.496 based on NIRSpec, NIRCam, and NIRISS observations obtained as part of the Early Release Observations program of the James Webb Space Telescope (JWST) and the far-infrared [C ii] 158 μm emission line detected by dedicated Atacama Large Millimeter/submillimeter Array (ALMA) observations. We determine the physical properties of S04590 from modeling of the spectral energy distribution (SED) and through the redshifted optical nebular emission lines detected with JWST/NIRSpec. The best-fit SED model reveals a low-mass (M ⋆ = 107.2–108 M ⊙) galaxy with a low oxygen abundance of 12+log(O/H)=7.16−0.12+0.10 derived from the strong nebular and auroral emission lines. Assuming that [C ii] effectively traces the interstellar medium, we estimate the total gas mass of the galaxy to be M gas = (8.0 ± 4.0) × 108 M ⊙ based on the luminosity and spatial extent of [C ii]. This yields an exceptionally high gas fraction, f gas = M gas/(M gas + M ⋆) ≳ 90%, though one still consistent with the range expected for low metallicity. We further derive the metal mass of the galaxy based on the gas mass and gas-phase metallicity, which we find to be consistent with the expected metal production from Type II supernovae. Finally, we make the first constraints on the dust-to-gas (DTG) and dust-to-metal (DTM) ratios of galaxies in the epoch of reionization at z ≳ 6, showing overall low mass ratios of logDTG < −3.8 and logDTM < −0.5, though they are consistent with established scaling relations and in particular with those of the local metal-poor galaxy I Zwicky 18. Our analysis highlights the synergy between ALMA and JWST in characterizing the gas, metal, and stellar content of the first generation of galaxies.