A transition in the accretion properties of radio-loud active nuclei
A transition in the accretion properties of radio-loud active nuclei
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DOI：
10.1111/j.1365-2966.2004.07822.x
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发表时间：
2004-03
影响因子：
4.8
通讯作者：
D. Marchesini;A. Celotti;L. F. S. -. Trieste;Rutgers University
中科院分区：
文献类型：
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作者：
D. Marchesini;A. Celotti;L. F. S. -. Trieste;Rutgers University
我们提出的证据存在的过渡的吸积特性的无线电大声源。对于一个射电星系和射电强类星体的样本，根据它们的扩展射电性质选择，吸积率估计从黑洞质量和核光度。推断出的分布是双峰的，以爱丁顿单位计，在1010 - 2量级的吸积率下（假设辐射效率为10%），可能跨越1-2个数量级的源很少。选择偏差不太可能是造成这种行为的原因。我们讨论了可能的物理解释，包括快速过渡到低吸积率，吸积模式/实际吸积率/辐射效率的变化，缺乏稳定的光盘解决方案在中间吸积率或几何薄流的射流形成过程的效率低下。这种跃迁可能类似于黑洞双星系统中的光谱态（和喷流）跃迁。
We present evidence for the presence of a transition in the accretion properties of radio-loud sources. For a sample of radio galaxies and radio-loud quasars, selected based on their extended radio properties, the accretion rate is estimated from the black hole mass and nuclear luminosity. The inferred distribution is bimodal, with a paucity of sources at accretion rates, in Eddington units, of the order of ∼10 -2 - assuming a radiative efficiency of 10 per cent -and possibly spanning 1-2 orders of magnitude. Selection biases are unlikely to be responsible for such behaviour. We discuss possible physical explanations, including a fast transition to low accretion rates, a change in the accretion mode/actual accretion rate/radiative efficiency, the lack of stable disc solutions at intermediate accretion rates or the inefficiency of the jet formation processes in geometrically thin flows. This transition might be analogous to spectral states (and jet) transitions in black hole binary systems.