National Central University, Graduate Institute of Astronomy, Taoyuan City, 32001, Taiwan.
Sci Rep. 2017 Feb 2;7:41617. doi: 10.1038/srep41617.
Distant luminous quasars provide important information on the growth of the first supermassive black holes, their host galaxies and the epoch of reionization. The identification of quasars is usually performed through detection of their Lyman-α line redshifted to 0.9 microns at z > 6.5. Here, we report the discovery of a very Lyman-α luminous quasar, PSO J006.1240 + 39.2219 at redshift z = 6.618, selected based on its red colour and multi-epoch detection of the Lyman-α emission in a single near-infrared band. The Lyman-α line luminosity of PSO J006.1240 + 39.2219 is unusually high and estimated to be 0.8 × 10 Solar luminosities (about 3% of the total quasar luminosity). The Lyman-α emission of PSO J006.1240 + 39.2219 shows fast variability on timescales of days in the quasar rest frame, which has never been detected in any of the known high-redshift quasars. The high luminosity of the Lyman-α line, its narrow width and fast variability resemble properties of local Narrow-Line Seyfert 1 galaxies which suggests that the quasar is likely at the active phase of the black hole growth accreting close or even beyond the Eddington limit.
遥远的类星体提供了关于第一代超大质量黑洞、它们的宿主星系以及再电离时代的重要信息。类星体的识别通常是通过检测其红移到 0.9 微米的莱曼-α线来实现的，红移值 z > 6.5。在这里，我们报告了一个非常亮的莱曼-α类星体 PSO J006.1240 + 39.2219 的发现，该类星体的红移值为 z = 6.618，是基于其红色颜色和在单个近红外波段中对莱曼-α发射的多时相检测而选择的。PSO J006.1240 + 39.2219 的莱曼-α线光度异常高，估计为 0.8 × 10 太阳光度（约为类星体总光度的 3%）。PSO J006.1240 + 39.2219 的莱曼-α发射在类星体静止帧上以天为单位的时间尺度上表现出快速变化，这在任何已知的高红移类星体中都从未检测到过。莱曼-α线的高光度、窄宽度和快速变化与本地窄线塞弗特 1 星系的性质相似，这表明类星体可能处于黑洞生长的活动阶段，其吸积接近甚至超过了爱丁顿极限。
