论文标题
在$ z \ sim6 $的星形星系中，$α$ -UV空间偏移的尺寸和普遍性
The Size and Pervasiveness of Ly$α$-UV Spatial Offsets in Star-Forming Galaxies at $z\sim6$
论文作者
论文摘要
We study the projected spatial offset between the ultraviolet continuum and Ly$α$ emission for 65 lensed and unlensed galaxies in the Epoch of Reionization ($5\leq z\leq7$), the first such study at these redshifts, in order to understand the potential for these offsets to confuse estimates of the Ly$α$ properties of galaxies observed in slit spectroscopy.尽管我们发现样本中约有40％的星系显示出明显的预测空间偏移（$ |δ_{lyα-uv} | $），但我们发现平均偏移量为0.61 $ \ pm $ 0.08 kpc。大约10％的样品中的一小部分显示出2-4 kpc的偏移量，大小比这些红移时典型星系的有效半径大。内部比较和与较低红移的研究的比较没有得到$ |δ_{lyα-uv} | $的显着证据。在我们自己的样本中，UV-Bright星系显示出偏移量的偏移倍数比其淡淡的同行大三倍，$ 0.89 $ \ pm $ 0.18和0.27 $ \ pm $ 0.05 kpc。我们认为，偏移可能不是合并过程的结果，而是由于恒星反馈引起的内部各向异性过程促进了$α$荧光和/或来自附近或流出的气体的反向散射。通过模拟观察简单模拟，量化了由于对各种观测设置的抵消效应而导致的$α$通量的减少。已经发现，如果纠正，除了最狭窄的缝隙宽度（<0.4''）外，没有平均偏移的星系的LY $α$光子损失不是一个限制因素。但是，对于最大的偏移而言，如果此类偏移主要垂直于缝隙主要轴，则在使用$ \ leq $ 1''的缝隙宽度（例如针对James Webb Space望远镜/NIRSPEC观察）计划的情况下，发现缝隙损失非常严重。 （简略）
We study the projected spatial offset between the ultraviolet continuum and Ly$α$ emission for 65 lensed and unlensed galaxies in the Epoch of Reionization ($5\leq z\leq7$), the first such study at these redshifts, in order to understand the potential for these offsets to confuse estimates of the Ly$α$ properties of galaxies observed in slit spectroscopy. While we find that ~40% of galaxies in our sample show significant projected spatial offsets ($|Δ_{Lyα-UV}|$), we find a modest average offset of 0.61$\pm$0.08 kpc. A small fraction of our sample, ~10%, exhibits offsets of 2-4 kpc, sizes that are larger than the effective radii of typical galaxies at these redshifts. An internal comparison and a comparison to studies at lower redshift yielded no significant evidence of evolution of $|Δ_{Lyα-UV}|$ with redshift. In our own sample, UV-bright galaxies showed offsets a factor of three greater than their fainter counterparts, 0.89$\pm$0.18 vs. 0.27$\pm$0.05 kpc, respectively. We argue that offsets are likely not the result of merging processes, but are rather due to internal anisotropic processes resulting from stellar feedback facilitates Ly$α$ fluorescence and/or backscattering from nearby or outflowing gas. The reduction in the Ly$α$ flux due to offset effects for various observational setups was quantified through mock observations of simple simulations. It was found that the loss of Ly$α$ photons for galaxies with average offsets is not, if corrected for, a limiting factor for all but the narrowest slit widths (<0.4''). However, for the largest offsets, if such offsets are mostly perpendicular to the slit major axis, slit losses were found to be extremely severe in cases where slit widths of $\leq$1'' were employed, such as those planned for James Webb Space Telescope/NIRSpec observations. (abridged)
