论文标题
与阿尔玛的双重约束：新[O III] 88 $ {\rmμ} $ m和dust-continuum观察结果揭示了$ z \ sim 7 $的发光LBG的ISM条件
Dual constraints with ALMA: new [O III] 88 ${\rm μ}$m and dust-continuum observations reveal the ISM conditions of luminous LBGs at $z \sim 7$
论文作者
论文摘要
我们提出了新的[O III] 88 $ {\rmμ} $ m观察五个明亮$ z \ sim 7 $ lyman-break星系光谱通过[C II] 158 $ {\ rmμ} $ M线通过[c ii] 158 $ {\ rmμ} $ m线，与最近的[O iii]检测中不同，这几乎将[C II]和[O III]的稳健（$5σ$）检测量（$5σ$）和[O III]的稳健（$5σ$）时代翻了一番。我们与剩余紫外线的新的深HST图像进行了多波长的比较，其紧凑的形态与[O III]追踪离子化气体很好地对齐。相比之下，我们发现在一个源中[N II] 205 $ {\ rmμ} $ m nontection a [n ii] 205 $ {\ rmμ} $ MM未检测的空间扩展[C II]发射可能会产生。我们发现光学[O III]和H $ {\rmβ} $线的等效宽度与[O III]/[C II]比率之间存在正相关，如局部金属贫困矮星系所示。具有高电离参数的年轻恒星种群的典型密度星云模型似乎可以充分再现远红外线。但是，令人惊讶的是，除非我们假设$ {\rmα} $/fe增强和近极氧化物的氧气丰度，否则我们的模型无法再现[O III] 88 $ {\rmμ} $ M的强度。在空间分辨的量表上，我们发现[O III]/[C II]显示了一种暂定的反相关，红外过量，$ l _ {\ rm ir}/l _ {\ rm uv} $，在本地宇宙的全球尺度上也可以看到。最后，我们介绍了远红外光谱能量分布拟合代码Mercurius，以表明一种源的灰尘测量值似乎有利于低防尘温度，并伴随着高尘埃质量。这意味着高恒星金属性产量，可能指向超新星以外的粉尘生产或晶粒生长机制。
We present new [O III] 88 ${\rm μ}$m observations of five bright $z \sim 7$ Lyman-break galaxies spectroscopically confirmed by ALMA through the [C II] 158 ${\rm μ}$m line, unlike recent [O III] detections where Lyman-${\rm α}$ was used. This nearly doubles the sample of Epoch of Reionisation galaxies with robust ($5 σ$) detections of [C II] and [O III]. We perform a multi-wavelength comparison with new deep HST images of the rest-frame UV, whose compact morphology aligns well with [O III] tracing ionised gas. By contrast, we find more spatially extended [C II] emission likely produced in neutral gas, as indicated by a [N II] 205 ${\rm μ}$m non-detection in one source. We find a positive correlation between the equivalent width of the optical [O III] and H${\rm β}$ lines and the [O III]/[C II] ratio, as seen in local metal-poor dwarf galaxies. Cloudy models of a nebula of typical density harbouring a young stellar population with a high ionisation parameter appear to adequately reproduce the far-infrared lines. Surprisingly, however, our models fail to reproduce the strength of [O III] 88 ${\rm μ}$m, unless we assume an ${\rm α}$/Fe enhancement and a near-solar nebular oxygen abundance. On spatially resolved scales, we find [O III]/[C II] shows a tentative anti-correlation with infrared excess, $L_{\rm IR}/L_{\rm UV}$, also seen on global scales in the local Universe. Finally, we introduce the far-infrared spectral energy distribution fitting code MERCURIUS to show that dust-continuum measurements of one source appear to favour a low dust temperature coupled with a high dust mass. This implies a high stellar metallicity yield and may point towards the need of dust production or grain-growth mechanisms beyond supernovae.
