AI 中文总结
本研究结合多卫星观测数据建模，发现PG 1407+265和RBS 229的X射线辐射可用双冕模型描述，约束了高光度AGN冕的性质及变异性差异。
AI 中文摘要
背景：活动星系核（AGN）的X射线辐射通常被认为源于吸积盘上方热冕的康普顿化过程，许多源中还观测到显著的软X射线超量，常被解释为暖康普顿化层的作用。目标：本研究对高光度射电宁静类星体PG 1407+265（红移z=0.94）和RBS 229（红移z=0.334）的X射线辐射冕进行研究，检验双冕模型是否能一致描述它们的宽带光谱。方法：本研究结合XMM-Newton EPIC与光学监测器数据、同时期的NuSTAR观测数据以及长期Swift监测数据，采用康普顿化模型对光谱进行建模。结果：两个类星体相对于标准αOX-LUV关系均为X射线强辐射体，其中PG 1407+265的偏离程度最大；它们的光谱可由暖的光学厚康普顿化成分（解释软超量）和产生硬X射线连续谱的热冕很好地拟合，两个源均在约70-80 keV处存在高能截断；RBS 229呈现中等强度的反射特征和弱的中性铁Kα线，而PG 1407+265未检测到显著的反射特征；RBS 229的暖冕参数在不同观测期保持一致，而PG 1407+265表现出强变异性，包括静止帧下延伸至约3 keV的极端软超量事件。结论：这些结果对研究较少的高光度AGN冕进行了约束，其截断能量大致符合AGN光度和吸积率的趋势，且低于正负电子对产生的失控极限；两个源的变异性差异表明暖冕会响应吸积流的变化，同时保持在狭窄的物理条件范围内。
英文摘要
Context. The X-ray emission of active galactic nuclei (AGNs) is commonly interpreted as arising from Comptonisation in a hot corona above the accretion disc. A prominent soft X-ray excess is also observed in many sources and is often explained by a warm Comptonising layer. Aims. We investigate the X-ray-emitting coronae of the luminous radio-quiet quasars PG 1407+265 ($z=0.94$) and RBS 229 ($z=0.334$), testing whether a two-corona scenario consistently describes their broadband spectra. Methods. We combine XMM-Newton EPIC and Optical Monitor data with simultaneous NuSTAR observations and long-term Swift monitoring, and model the spectra using Comptonisation models. Results. Both quasars are X-ray loud relative to the standard $α_{\rm OX}$-$L_{\rm UV}$ relation, with PG 1407+265 showing the strongest deviation. Their spectra are well reproduced by a warm, optically thick Comptonising component accounting for the soft excess and a hot corona producing the hard X-ray continuum. Both sources show high-energy cut-offs at approximately 70-80 keV. RBS 229 exhibits moderate reflection and a weak neutral Fe K-alpha line, while no significant reflection features are detected in PG 1407+265. The warm-corona parameters of RBS 229 remain consistent across epochs, whereas PG 1407+265 shows strong variability, including an extreme soft-excess episode extending to approximately 3 keV in the rest frame. Conclusions. These results constrain AGN coronae in the poorly explored high-luminosity regime. The cut-offs are broadly consistent with trends in AGN luminosity and accretion rate and remain below the runaway pair-production limit. The contrasting variability suggests that the warm corona responds to changes in the accretion flow while remaining within a narrow range of physical conditions.
Comments17 pages, 11 figures, accepted for publication in Astronomy & Astrophysics
DOI：10.1051/0004-6361/202660733
