The first high-redshift changing-look quasars
The first high-redshift changing-look quasars
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DOI：
10.1093/mnras/staa2415
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发表时间：
2019-12
影响因子：
4.8
通讯作者：
N. Ross;M. Graham;G. Calderone;K. Ford;K. Ford;B. McKernan;B. McKernan;D. Stern
中科院分区：
文献类型：
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作者：
N. Ross;M. Graham;G. Calderone;K. Ford;K. Ford;B. McKernan;B. McKernan;D. Stern
我们报道了三个红移z > 2的类星体，它们的Civ发射线发生了巨大的变化，这是第一个在高红移的变貌类星体（CLQ）。这也是第一次在高电离发射线中看到外观变化的行为。SDSS J1205+3422、J1638+2827和J2228 + 2201在它们观察到的光学光变曲线中显示出有趣的行为，随后的光谱学显示出C iv宽发射线的显著变化，在240-1640 d的静止帧时间尺度上显示出线的崩溃和出现。这是快速的变化，特别是当考虑到维里黑洞质量估计MBH > 109 M的所有三个类星体。从三个类星体的连续谱和发射线测量显示的连续等效宽度平面的变化与CLQs看到的边缘上的完整的人口分布，并显示出一个内在的鲍德温效应的迹象。我们把这些观察与最近的状态变化模型的背景下，并注意到，即使在他们观察到的低状态，C iv CLQ一般都在爱丁顿光度的105%以上。
We report on three redshift z > 2 quasars with dramatic changes in their C iv emission lines, the first sample of changing-look quasars (CLQs) at high redshift. This is also the first time the changing-look behaviour has been seen in a high-ionization emission line. SDSS J1205+3422, J1638+2827, and J2228 + 2201 show interesting behaviour in their observed optical light curves, and subsequent spectroscopy shows significant changes in the C iv broad emission line, with both line collapse and emergence being displayed on rest-frame time-scales of ∼240–1640 d. These are rapid changes, especially when considering virial black hole mass estimates of MBH > 109M⊙ for all three quasars. Continuum and emission line measurements from the three quasars show changes in the continuum-equivalent width plane with the CLQs seen to be on the edge of the full population distribution, and showing indications of an intrinsic Baldwin effect. We put these observations in context with recent state-change models, and note that even in their observed low-state, the C iv CLQs are generally above ∼5 per cent in Eddington luminosity.