AI 中文总结
本研究利用兹威基瞬变巡天的不规则采样光变曲线，结合斯莱皮安小波方差和凝聚层次聚类，在无光谱的情况下对类星体类型进行分类，1型恢复率99%、2型87%，为大规模类星体分类提供了新方法。
AI 中文摘要
区分1型和2型类星体对理解活动星系的吸积机制、黑洞质量标度关系、盘不稳定性及反馈过程具有重要意义。尽管光谱学能提供可靠的分类，但现代巡天观测到数百万个类星体，获取优质光谱需耗费大量时间和资源，难以实现大规模应用；而测光方面，类星体光变曲线的采样始终不规则，且受测光巡天的具体情况影响，分析难度较大。本研究表明，我们可利用兹威基瞬变巡天（Zwicky Transient Facility）的不规则采样光变曲线，结合斯莱皮安小波方差（Slepian Wavelet Variance）实现无光谱的类星体类型分类。该技术能将光变曲线的方差分解为多个时间尺度。我们仅基于MILLIQUAS星表中516个1型类星体和238个2型类星体的小波方差曲线，使用凝聚层次聚类进行分类，1型类星体的恢复率达99%，2型类星体为87%，少数分类错误的类星体其光变行为与光谱类型相反。与结构函数和阻尼随机游走模型不同，斯莱皮安小波方差可提供短、长时间尺度上变异性的互补、与模型无关的视角。
英文摘要
Distinguishing between Type 1 and Type 2 quasars is important because it helps us understand accretion regimes, black hole mass scaling, disk instabilities and feedback processes in active galaxies. Although spectroscopy provides robust classification, it does not scale well with the millions of quasars observed in modern surveys, as it requires substantial time and resources to acquire a good spectrum. On the photometry side, quasar light curves are always irregularly sampled and affected by the specifics of photometric surveys, making them difficult to analyze. In this work, we show that we can use irregularly sampled light curves from the Zwicky Transient Facility to classify quasar types without a spectrum, using Slepian Wavelet Variance. This technique allows us to decompose the variance of light curves into multiple timescales. We use agglomerative hierarchical clustering to classify 516 Type 1 and 238 Type 2 quasars from the MILLIQUAS catalogue, solely based on their wavelet variance curves. We obtain a recovery rate of 99% for Type 1 and 87% for Type 2 quasars, and the few misclassified quasars show the opposite variability behaviour to their spectral type. In contrast to structure functions and the Damped Random Walk model, Slepian Wavelet Variance offers a complementary, model-independent view of variability across short and long timescales.
Comments22 pages, 15 figures. Accepted for publication in PASP
