论文标题
通过黑暗能源调查将自动形态分类推向其极限
Pushing automated morphological classifications to their limits with the Dark Energy Survey
论文作者
论文摘要
我们使用有监督的深度学习算法介绍了来自黑暗能源调查(DES)数据1(DR1)的2700万美元星系的形态学分类。分类方案分开:(a)早期类型的星系(ETG)与晚期(LTGS); (b)边缘面对面的星系。我们的卷积神经网络(CNN)在具有先前已知分类的一小部分DES对象中进行了训练。这些通常具有$ \ mathrm {m} _r \ sillsim 17.7〜 \ mathrm {mag} $;我们通过模拟具有明确确定的分类的明亮对象,如果它们处于较高的红移,我们将对象建模为$ \ mathrm {m} _r <21.5 $ mag。 CNN在训练组中达到97 \%的精度至$ \ Mathrm {M} _r <21.5 $,这表明他们能够比人眼更准确地恢复功能。然后,我们使用训练有素的CNN来对其他绝大多数DES图像进行分类。最终目录包括每个分类方案的五个独立的CNN预测,有助于确定CNN预测是否可靠。我们分别以$ \ sim $ 87 \%和73%的目录获得ETG与LTG和Edge-On与Face-On模型的安全性分类。结合两个分类(a)和(b)有助于提高ETG样品的纯度并识别边缘膜状星系(作为具有高椭圆率的ETG)。如果可以进行比较,我们的分类与Sérsic索引(\ textit {n}),椭圆度($ε$)和光谱类型非常相关,即使对于薄弱的星系也是如此。这是迄今为止自动化星系形态的最大的多波段目录。
We present morphological classifications of $\sim$27 million galaxies from the Dark Energy Survey (DES) Data Release 1 (DR1) using a supervised deep learning algorithm. The classification scheme separates: (a) early-type galaxies (ETGs) from late-types (LTGs); and (b) face-on galaxies from edge-on. Our Convolutional Neural Networks (CNNs) are trained on a small subset of DES objects with previously known classifications. These typically have $\mathrm{m}_r \lesssim 17.7~\mathrm{mag}$; we model fainter objects to $\mathrm{m}_r < 21.5$ mag by simulating what the brighter objects with well determined classifications would look like if they were at higher redshifts. The CNNs reach 97\% accuracy to $\mathrm{m}_r<21.5$ on their training sets, suggesting that they are able to recover features more accurately than the human eye. We then used the trained CNNs to classify the vast majority of the other DES images. The final catalog comprises five independent CNN predictions for each classification scheme, helping to determine if the CNN predictions are robust or not. We obtain secure classifications for $\sim$ 87\% and 73\% of the catalog for the ETG vs. LTG and edge-on vs. face-on models, respectively. Combining the two classifications (a) and (b) helps to increase the purity of the ETG sample and to identify edge-on lenticular galaxies (as ETGs with high ellipticity). Where a comparison is possible, our classifications correlate very well with Sérsic index (\textit{n}), ellipticity ($ε$) and spectral type, even for the fainter galaxies. This is the largest multi-band catalog of automated galaxy morphologies to date.