STATISTICAL PROPERTIES OF MULTI-EPOCH SPECTRAL VARIABILITY OF SDSS STRIPE 82 QUASARS
STATISTICAL PROPERTIES OF MULTI-EPOCH SPECTRAL VARIABILITY OF SDSS STRIPE 82 QUASARS
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DOI：
10.1088/0004-637x/783/1/46
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发表时间：
2014-01
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通讯作者：
M. Kokubo;T. Morokuma;T. Minezaki;M. Doi;T. Kawaguchi;H. Sameshima;Shin Mineshige Department of Astronomy;School of Materials Science;T. U. O. Tokyo;K. I. F. T. Physics;M. Universe;Todai Institutes for Advanced Study;Research Center for the Early Universe;D. Physics;Information Science;Y. University;I. O. Space;Astronautical Science;Japan Aerospace Exploration Agency;Center of Astro Engineering;Department of Electrical Engineering;P. U. C. D. Chile
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作者：
M. Kokubo;T. Morokuma;T. Minezaki;M. Doi;T. Kawaguchi;H. Sameshima;Shin Mineshige Department of Astronomy;School of Materials Science;T. U. O. Tokyo;K. I. F. T. Physics;M. Universe;Todai Institutes for Advanced Study;Research Center for the Early Universe;D. Physics;Information Science;Y. University;I. O. Space;Astronautical Science;Japan Aerospace Exploration Agency;Center of Astro Engineering;Department of Electrical Engineering;P. U. C. D. Chile
我们研究了近9,000个类星体(0<；z<；4)的紫外光(Lyα1216？)光谱变率。类星体光曲线通量-通量空间中的回归斜率直接测量通量差光谱的颜色，然后通过仔细观察回归斜率的红移依赖关系可以得到通量差光谱的光谱形状。首先，我们证实了当类星体变得更亮时，观测到的类星体光谱变得更蓝。我们推导出合成差谱的谱指数为(以的形式)，它明显比合成光谱的光谱指数蓝。我们还发现，具有不同质量吸积率的吸积盘模型不能解释连续谱的变异性。其次，我们考察了宽发射线变化对颜色红移空间的影响。对“小蓝凸点”的可变性进行了广泛的讨论。结果表明，与巴尔默发射线和高电离线相比，Mg II和Fe II的低电离线变化较小，并且在∼30 0 0A附近，巴尔默连续谱是主要的变化源。将这些结果与前人的研究结果进行了比较，并讨论了连续谱和发射线变化的物理机制。
We investigate the UV–optical (longward of Lyα 1216 Å) spectral variability of nearly 9000 quasars (0 < z < 4) using multi-epoch photometric data within the SDSS Stripe 82 region. The regression slope in the flux–flux space of a quasar light curve directly measures the color of the flux difference spectrum, then the spectral shape of the flux difference spectra can be derived by taking a careful look at the redshift dependence of the regression slopes. First, we confirm that the observed quasar spectrum becomes bluer when the quasar becomes brighter. We infer the spectral index of the composite difference spectrum as (in the form of ), which is significantly bluer than that of the composite spectrum . We also show that the continuum variability cannot be explained by accretion disk models with varying mass accretion rates. Second, we examine the effects of broad emission line variability on the color–redshift space. The variability of the “Small Blue Bump” is extensively discussed. We show that the low-ionization lines of Mg ii and Fe ii are less variable compared to Balmer emission lines and high-ionization lines, and the Balmer continuum is the dominant variable source around ∼3000 Å. These results are compared with previous studies, and the physical mechanisms of the variability of the continuum and emission lines are discussed.