标题： DESI类星体（QSO）样本的初步目标选择 显示英文标题

标题： Preliminary Target Selection for the DESI Quasar (QSO) Sample

摘要： DESI巡天将利用类星体作为直接暗物质示踪物，在红移范围为$0.9<z<2.1$至$z>2.1$的类星体Ly-$\alpha$森林测量大尺度结构。我们提出了两种基于光学（$g, r, z$）和红外（$W1, W2$）三个光学带和两个红外带的成像选择DESI候选类星体的方法。第一种方法使用传统的颜色切割，第二种方法则利用机器学习算法。 显示英文摘要

摘要： The DESI survey will measure large-scale structure using quasars as direct tracers of dark matter in the redshift range $0.9<z<2.1$ and using quasar Ly-$\alpha$ forests at $z>2.1$. We present two methods to select candidate quasars for DESI based on imaging in three optical ($g, r, z$) and two infrared ($W1, W2$) bands. The first method uses traditional color cuts and the second utilizes a machine-learning algorithm.