论文标题
通过神经网络确定Lyman-Alpha发射器的系统性红移并改善测得的大规模集群
Determining the systemic redshift of Lyman-alpha emitters with neural networks and improving the measured large-scale clustering
论文作者
论文摘要
我们探索如何减轻Lyman-$α$发射器(LAES)样品的聚类畸变,这是由于其Lyman-$α$(ly $α$)波长在其LY $α$ line crom crom crom crom profiles中引起的。我们使用以前LAE理论模型的LY $α$线轮廓,其中包括星际和星际培养基中的辐射转移。我们介绍了一种新颖的方法,可以使用神经网络从其LY $α$线中测量LAE的系统性红移。详细说明,我们假设在整个LAE人群中,它们的系统性红移是通过其他光谱特征确切确定的。然后,我们使用此子集来训练一个神经网络,该神经网络可以预测$ ly $α$线的轮廓。我们测试了两个不同的训练集:i)LAES是同质选择的,ii)仅选择了最亮的LAE。与文献中先前的方法相比,我们的方法论在确定LY $α$波长方面都显着提高了准确性和精度。实际上,将我们的算法应用于理想的$α$线轮廓之后,我们恢复了未扰动的聚类,将其恢复到1cmpc/h。然后,我们通过降低其质量来测试方法论的性能。即使LY $α$线的轮廓质量大大降低,机器学习技术也可以很好地工作。我们得出的结论是,诸如HETDEX之类的LAE调查将受益于高精度的确定亚种群的系统性红移,并应用我们的方法来估计银河系其余样品的系统性红移。
We explore how to mitigate the clustering distortions in Lyman-$α$ emitters (LAEs) samples caused by the miss-identification of the Lyman-$α$ (Ly$α$) wavelength in their Ly$α$ line profiles. We use the Ly$α$ line profiles from our previous LAE theoretical model that includes radiative transfer in the interstellar and intergalactic mediums. We introduce a novel approach to measure the systemic redshift of LAEs from their Ly$α$ line using neural networks. In detail, we assume that, for a fraction of the whole LAE population their systemic redshift is determined precisely through other spectral features. We then use this subset to train a neural network that predicts the Ly$α$ wavelength given a Ly$α$ line profile. We test two different training sets: i) the LAEs are selected homogeneously and ii) only the brightest LAEs are selected. In comparison with previous approaches in the literature, our methodology improves significantly both accuracy and precision in determining the Ly$α$ wavelength. In fact, after applying our algorithm in ideal Ly$α$ line profiles, we recover the clustering unperturbed down to 1cMpc/h. Then, we test the performance of our methodology in realistic Ly$α$ line profiles by downgrading their quality. The machine learning techniques work well even if the Ly$α$ line profile quality is decreased considerably. We conclude that LAE surveys such as HETDEX would benefit from determining with high accuracy the systemic redshift of a subpopulation and applying our methodology to estimate the systemic redshift of the rest of the galaxy sample.