AI 中文总结
本文针对两个转变时标短于1年的快速变光活动星系核，改进相关模型并结合观测数据，证实其转变时标可由内ADAF坍缩机制解释，为CL AGN短转变时标提供了物理依据。
AI 中文摘要
SDSS J0225+0030和SDSS J1723+5504是两个开启型变光活动星系核（CL AGN），其转变时标短于1年，这类短时间尺度对现有CL AGN物理模型构成挑战。本文通过探究两种可能机制研究该问题：首先，考虑大尺度磁场对粘滞时标的影响，该效应可提升吸积盘的径向速度，但此模型给出的时标仍显著长于1年；其次，改进文献[2025ApJ...988..207L]提出的模型，该模型认为亮态下的内薄盘可能由暗态下的径移主导吸积流（ADAF）坍缩形成，而非被外薄盘的径移过程取代。我们通过亮态与暗态间光变的观测变化，重新估算内ADAF与外薄盘间的转变半径R_tr；结果发现，这两个天体因拥有约10^9 M⊙的大黑洞质量和约0.01的爱丁顿标度吸积率，内盘区域气体温度低至约10^4 K，使得R_tr可显著减小；经修正后的模型给出的冷却时标与观测到的转变时标相当。
英文摘要
SDSS J0225+0030 and SDSS J1723+5504 are two turn-on changing-look active galactic nuclei (CL AGNs) with transition timescales shorter than one year. Such short timescales pose a challenge for the current physical models of CL AGNs. We investigate this issue by exploring two possible mechanisms in this work. First, we consider the effect of a large-scale magnetic field on the viscous timescale, which can increase the radial velocity of the accretion disk. However, it is found that the timescale given by this model remains significantly longer than one year. Second, we improve the model of \citet{2025ApJ...988..207L}, which proposed that the inner thin disk in the bright state may form through the collapse of an advection-dominated accretion flow (ADAF) in the dim state, rather than being replaced by the advection of the outer thin disk. We re-estimate the transition radius $R_{\rm tr}$ between the inner ADAF and the outer thin disk through the observed variation of optical flux between the bright state and dim state. It is found that $R_{\rm tr}$ can be significantly reduced in these two objects owing to the lower gas temperature in the inner disk region (of the order of $10^4$ K), resulting from their large black hole masses ($\sim 10^9 M_{\odot}$) and small Eddington-scaled mass accretion rates ($\sim 0.01$). The cooling timescales given by the revised model in these two objects are found to be comparable to the observed transition timescales.
Comments10 pages, 4 figures, 2 tables, accepted by ApJ
