AI 中文总结
本研究基于SDSS-V，用GUA和Skewt-QSO方法构建了含25万余颗高纯度类星体的样本，为南半球时域巡天及类星体与SMBH演化研究提供了可靠参考
AI 中文摘要
类星体是能为超大质量黑洞（SMBH）及其吸积流的物理与演化、星系演化乃至宇宙学提供研究线索的明亮天体。本研究基于正在开展的第五代斯隆数字巡天（SDSS-V）及其独特的双半球、大视场、多目标光谱观测能力开展探索性研究，旨在构建一份全面的全天类星体样本。目标天体通过两种新方法GUA和Skewt-QSO选定，这两种方法主要依赖WISE和盖亚的数据，旨在弥补此前大型类星体样本的不足。本样本包含超过25万个经光谱确认的红移z~5的类星体，其中南半球有上万颗新识别的类星体。所选方法的纯度很高，采集的光谱中超过80%为真正的类星体，主要的污染天体是M型恒星。我们采用的详细光谱分解流程显示，样本中的类星体涵盖了广泛的光度范围（Lbol~$10^{44}-10^{48} erg s^{-1}$）、SMBH质量范围（MBH~$10^6-10^{10}$ Msun）和吸积率范围（L/LEdd~0.01-1）。一旦考虑不同巡天深度相关的潜在选择偏差，这些属性的分布与基于前几代SDSV的以往类星体星表的分布一致。我们的发现证实，基于光学+红外色指数和/或天体测量学的新型选择方法，可在大天区范围内产出大尺寸、高纯度的类星体样本，适用于无法获取更精细的多波段测光或X射线、射电多波段数据的情况。这份将持续扩容的SDSS-V样本，为未来的南半球时域巡天建立了可靠参考，同时深化并补充了我们对类星体人口统计学和SMBH演化的理解。
英文摘要
Quasars are luminous objects that provide insights into the physics and evolution of supermassive black holes (SMBHs) and their accretion flows, galaxy evolution, and even cosmology. In this study, we present an exploratory study based on the ongoing fifth generation of the Sloan Digital Sky Survey (SDSS-V) and its unique dual-hemisphere, wide-field, and multi-object spectroscopic capabilities, with the aim of creating a comprehensive, all-sky quasar sample. The targets were selected through two novel methods, GUA and Skewt-QSO, that rely primarily on data from WISE and Gaia, aiming to address gaps in previous large quasar samples. Our sample includes over 250,000 spectroscopically confirmed quasars reaching z~5, with tens of thousands of newly identified quasars in the southern hemisphere. The selection methods are highly pure, with well over 80% of the spectra collected being genuine quasars; the main contaminants are M-type stars. The detailed spectral decomposition procedure we employed shows that the quasars in the sample span a wide range of luminosities (Lbol~$10^{44}-10^{48} erg s^{-1}$), SMBH masses (MBH~$10^6-10^{10}$ Msun), and accretion rates (L/LEdd~0.01-1). The distributions of these properties are consistent with those of previous quasar catalogs, which are based on past generations of SDSS, once we account for potential selection biases related to the various survey depths. Our findings confirm that novel selection methods based on optical+IR colors and/or astrometry can yield a large, high-purity quasar sample over wide sky areas, including in cases where more nuanced multi-band photometry and/or multi-wavelength data in the X-ray or radio is not available. This SDSS-V sample, which will continue to grow, establishes a robust reference for future southern (time-domain) surveys, while enhancing and complementing our understanding of quasar demographics and SMBH evolution.
CommentsResubmitted to ApJ on 28 July 2026 after addressing the referee report. The data will be available in SDSS-V/DR20
