The discovery of rest-frame UV colour gradients and a diversity of dust morphologies in bright z ? 7 Lyman-break galaxies
The discovery of rest-frame UV colour gradients and a diversity of dust morphologies in bright z ? 7 Lyman-break galaxies
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发现静止帧 UV 颜色梯度和亮 z 中灰尘形态的多样性？
DOI：
10.1093/mnras/stab3744
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发表时间：
2022
影响因子：
4.8
通讯作者：
Bowler R
中科院分区：
文献类型：
--
作者：
Bowler R
我们提出了深阿尔马尘埃连续观测样本的发光（MUV<-22）恒星形成星系atz 107。我们在远红外（FIR）中检测到六个源中的五个，在不需要叠加的情况下提供对遮蔽星星形成率（SFR）和红外过量β（IRX-β）关系的关键约束。尽管星系显示出蓝色的静止坐标系紫外线（UV）斜率（β <$−2），我们发现总SFR的35%-75%是模糊的。我们发现，这两个星系源的IRX-β关系与本星系的IRX-β关系一致。使用我们的相对高分辨率（FWHM）的观测，我们确定了样品中的灰尘形态的多样性。我们发现这两个紧凑的排放，出现相对于未遮挡的组件和扩展的灰尘排放，是同空间的休息帧紫外光偏移。在大多数来源中，我们检测到强烈的静止帧紫外线颜色梯度（高达Δβ = 0.7-1.4），如多波段UltraVISTA地基数据所探测的那样。所观察到的较红的颜色在空间上与FIR检测的位置相关。我们的研究结果表明，即使在明亮的Lyman break星系atz = 7中，星星形成的峰值通常也位于静止坐标系UV中较暗、较红的区域，这些区域具有≥ 0.8的模糊分数。这些观测结果不仅证明了再电离时期尘埃遮蔽星星形成的重要性，而且还提供了一个令人兴奋的体验，即将从JWST和高分辨率阿尔马后续观测中获得的丰富的空间分辨数据集。
We present deep ALMA dust continuum observations for a sample of luminous (MUV< −22) star-forming galaxies atz≃ 7. We detect five of the six sources in the far-infrared (FIR), providing key constraints on the obscured star formation rate (SFR) and the infrared-excess-β (IRX–β) relation without the need for stacking. Despite the galaxies showing blue rest-frame ultraviolet (UV) slopes (β ≃ −2) we find that 35–75 per cent of the total SFR is obscured. We find the IRX–β relation derived for thesez≃ 7 sources is consistent with that found for local starburst galaxies. Using our relatively high-resolution (FWHM) observations we identify a diversity of dust morphologies in the sample. We find both compact emission that appears offset relative to the unobscured components and extended dust emission that is co-spatial with the rest-frame UV light. In the majority of the sources, we detect strong rest-frame UV colour gradients (with up to Δβ ≃ 0.7–1.4) as probed by the multiband UltraVISTA ground-based data. The observed redder colours are spatially correlated with the location of the FIR detection. Our results show that even in bright Lyman-break galaxies atz≃ 7 the peak of the star formation is typically hosted by the fainter, redder, regions in the rest-frame UV, which have an obscured fraction offobs≥ 0.8. As well as demonstrating the importance of dust obscured star formation within the Epoch of Reionization, these observations provide an exciting taster of the rich spatially resolved data sets that will be obtained fromJWSTand high-resolution ALMA follow-up at these redshifts.