AI 中文总结
该研究利用BASS DR2样本，通过热辐射光球的观测特征，为无视界致密天体提供群体层面的观测约束，扩展了此前针对M87*和Sgr A*的视界测试。
AI 中文摘要
Swift 爆发alert望远镜活动星系核光谱巡天（BASS DR2）提供了最大、最完整的明亮本地（z<0.1）活动星系核（AGNs）样本之一，具备高质量光谱测量数据。这些源通常在克尔黑洞框架下被解释，但已提出多种无视界致密天体场景作为替代，包括裸奇点、黑洞模拟物及其他奇异致密天体。在很大程度上独立于所采用的特定无视界模型的物理性质，吸积驱动的热辐射光球预计会在天文短时间尺度内形成。本文研究该光球的存在是否与BASS AGNs合适子样本的观测性质一致。我们发现，所有样本中均不存在此类光谱特征，且可排除相当一部分天体中存在该特征的可能性；对于剩余源，适度提升观测灵敏度和光谱覆盖范围即可实现可靠排除。我们的结果将此前针对M87*和Sgr A*的视界尺度测试扩展至大量AGNs样本，提供了强有力的群体层面证据反对无视界替代模型。最后，我们概述了未来观测策略，可进一步收紧这些约束并显著增加需满足视界要求的天体数量。
英文摘要
The Swift Burst Alert Telescope Active Galactic Nuclei Spectroscopic Survey (BASS DR2) provides one of the largest and most complete samples of bright, local (z < 0.1) active galactic nuclei (AGNs) with high-quality spectroscopic measurements. These sources are typically interpreted within the framework of Kerr black holes; however, a wide range of horizonless compact-object scenarios-including naked singularities, black hole mimickers, and other exotic compact objects-have been proposed as alternatives. Largely independent of the physics of the particular horizonless model invoked, an accretion powered, thermally radiating photosphere is expected to develop on astronomically short timescales. In this paper, we investigate whether the presence of such a photosphere is consistent with the observed properties of an appropriate subsample of BASS AGNs. We find that in no instances is such a spectral feature present, and can exclude its existence in significant fraction of objects. For the remaining sources, modest improvements in observational sensitivity and spectral coverage could enable robust exclusion. Our results extend previous horizon-scale tests performed for M87* and Sgr A* to a large AGN population, providing strong, population-level evidence against horizonless alternatives. We conclude by outlining future observational strategies that can further tighten these constraints and significantly increase the number of objects for which horizons are required.
