论文标题
灰尘和类星体变化的固有光谱指数：最内向的圆形轨道上有限应力的提示
Dust and the intrinsic spectral index of quasar variations: hints of finite stress at the innermost stable circular orbit
论文作者
论文摘要
我们提出了一项研究，该研究对SDSS Southern调查的多个上述UGRIZ光度法进行了9242个光谱固定的类星体。通过将可分离线性模型拟合到每个类星体的光谱变化，我们将它们的五波段光谱分布分解为可变（盘）和不可变化（宿主星系）组件。在对圆盘谱进行建模时，我们包括通过宿主星系在视线上通过尘埃衰减到其核。我们考虑了五种常用的衰减定律，发现最佳描述是通过类似于小麦芽云的灰尘，从相对较弱的2175AA吸收特征中推断出缺乏碳质晶粒。我们继续为跨越700至8000AA的类星体变化构建复合频谱。通过改变假定的幂律$l_ν\proptoν^α$频谱斜率，我们找到了最佳拟合值$α= 0.71 \ pm0.02 $，不包括在很高的信心中，规范$l_ν\ proptov^{1/3} $用于稳态增载盘，并带有$ t \ r^r^3/3/3/3/3/4相反，观察到的类星体变化的蓝光谱指数支持木乃伊和巴布斯的模型，在该模型中，由于有限的磁性磁性应力在内部稳定的圆形圆形轨道萃取能量和垂直于Blackball Blackhole的稳定稳定的圆形轨道萃取动力和轴向启动下，温度较高的$ t \ propto r^{ - 7/8} $都会形成。
We present a study of 9242 spectroscopically-confirmed quasars with multi-epoch ugriz photometry from the SDSS Southern Survey. By fitting a separable linear model to each quasar's spectral variations, we decompose their five-band spectral energy distributions into variable (disc) and non-variable (host galaxy) components. In modelling the disc spectra, we include attenuation by dust on the line of sight through the host galaxy to its nucleus. We consider five commonly used attenuation laws, and find that the best description is by dust similar to that of the Small Magellanic Cloud, inferring a lack of carbonaceous grains from the relatively weak 2175AA absorption feature. We go on to construct a composite spectrum for the quasar variations spanning 700 to 8000AA. By varying the assumed power-law $L_ν\proptoν^α$ spectral slope, we find a best-fit value $α=0.71\pm0.02$, excluding at high confidence the canonical $L_ν\proptoν^{1/3}$ prediction for a steady-state accretion disc with a $T\propto r^{-3/4}$ temperature profile. The bluer spectral index of the observed quasar variations instead supports the model of Mummery & Balbus in which a steeper temperature profile, $T\propto r^{-7/8}$, develops as a result of finite magnetically-induced stress at the innermost stable circular orbit extracting energy and angular momentum from the black hole spin.
