Now You See It, Now You Don't: The Disappearing Central Engine of the Quasar J1011+5442
Now You See It, Now You Don't: The Disappearing Central Engine of the Quasar J1011+5442
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DOI：
10.1093/mnras/stv2385
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发表时间：
2015-09
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影响因子：
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通讯作者：
J. Runnoe;S. Cales;J. Ruan;M. Eracleous;S. Anderson;Yue Shen;P. Green;E. Morganson;S. LaMassa-S.-L
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文献类型：
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作者：
J. Runnoe;S. Cales;J. Ruan;M. Eracleous;S. Anderson;Yue Shen;P. Green;E. Morganson;S. LaMassa-S.-L
我们报告了一个新的“改变外观”类星体，SDSS J101152.98+544206.4，通过重复光谱从时域光谱调查的发现。这是一个小的，但不断增长的类星体，其蓝色连续谱和广泛的光学发射线已被观察到下降了一个大的因素，在大约十年的时间尺度。这个类星体的5100埃单色连续光度在小于9.7年的静止帧时间间隔内下降了9.8倍，而宽的H-α光度在相同的时间内下降了55倍。宽的H-α线的宽度在昏暗状态下增加，使得从适当的单历元标度关系导出的黑洞质量在两个历元之间在3倍内一致。窄发射谱线的通量在不同时期之间似乎没有变化。卡塔利纳巡天获得的光变曲线表明，这种转变发生在大约500天的静止帧时间间隔内。我们研究了最近文献中提出的这种转变的三种可能机制。朝向中央引擎的变红的突然变化是不利的，因为在模糊中央引擎的时间尺度和观察到的转变的时间尺度之间存在实质性差异。衰减的潮汐破裂耀斑与光变曲线的衰减率一致，但与衰减前的长时间明亮状态不一致，这种情况也不能提供发射线光度所需的功率。超大质量黑洞吸积速率的突然下降似乎是快速变暗的最合理解释。
We report the discovery of a new "changing-look" quasar, SDSS J101152.98+544206.4, through repeat spectroscopy from the Time Domain Spectroscopic Survey. This is an addition to a small but growing set of quasars whose blue continua and broad optical emission lines have been observed to decline by a large factor on a time scale of approximately a decade. The 5100 Angstrom monochromatic continuum luminosity of this quasar drops by a factor of > 9.8 in a rest-frame time interval of < 9.7 years, while the broad H-alpha luminosity drops by a factor of 55 in the same amount of time. The width of the broad H-alpha line increases in the dim state such that the black hole mass derived from the appropriate single-epoch scaling relation agrees between the two epochs within a factor of 3. The fluxes of the narrow emission lines do not appear to change between epochs. The light curve obtained by the Catalina Sky Survey suggests that the transition occurs within a rest-frame time interval of approximately 500 days. We examine three possible mechanisms for this transition suggested in the recent literature. An abrupt change in the reddening towards the central engine is disfavored by the substantial difference between the timescale to obscure the central engine and the observed timescale of the transition. A decaying tidal disruption flare is consistent with the decay rate of the light curve but not with the prolonged bright state preceding the decay, nor can this scenario provide the power required by the luminosities of the emission lines. An abrupt drop in the accretion rate onto the supermassive black hole appears to be the most plausible explanation for the rapid dimming.