论文标题
随机过程作为类星体光度函数的双重动力法的起源
Stochastic Processes as the Origin of the Double-Power Law Shape of the Quasar Luminosity Function
论文作者
论文摘要
类星体光度函数（QLF）提供了对黑洞和星系早期共同进化的见解。与Redshift $ Z \ SIM6 $相比，它的表征是从观察到的，具有双重幂律形状的明确证据，与基础深色halo质量功能的Schechter样形式相反。我们通过考虑确定给定宿主光环和红移的类星体发光度引起的随机性的影响来研究这些分布的差异。我们采用条件光度函数并构建中值类星体幅度与光晕质量$ m_ {uv，\ rm {c}}}（m _ {\ rm {h}}）$与log-normal in Louminortose in Luminosity in Luminosity sctitch $σ$ sctation $σ$，和责任cycle-cycle $ s} $ z \ gtrsim4 $。我们表明，为了重现观测到的QLF，$σ= 0 $丰度匹配需要所有最亮的类星体托管在最稀有的最庞大的深色污液中（随着$ M_ {uv，\ rm \ rm {c}}}}}}/m _ {\ rm _ {\ rm {\ rm {\ rm {相反，对于$σ> 0 $，最明亮的类星体可以是相对常见的深色晕孔中托管的过度露骨异常值。在这种情况下，中值类星体的幅度与光环质量关系，$ m_ {uv，\ rm {c}} $，在高端变平，正如由于反馈而自我调节的增长中所预期的。我们采样了$σ$和$ε_ {\ rm {dc}} $的参数空间，并显示$ m_ {uv，\ rm {c}} $ flattens $ m _ {\ rm {\ rm {h}}} $ε_ {\ rm {dc}} <10^{ - 2} $。具有$ε_ {\ rm {dc}} \ sim1 $的模型需要一个高质量阈值接近$ m _ {\ rm {h}} \ gtrsim10^{13} m _ {\ odot} $。我们研究了$ε_ {\ rm {dc}} $和$σ$对聚类测量的影响，发现对$σ> 0.3 $的聚类没有亮度依赖性，与Subaru HSC的最新观察结果一致。
The Quasar Luminosity Function (QLF) offers insight into the early co-evolution of black holes and galaxies. It has been characterized observationally up to redshift $z\sim6$ with clear evidence of a double power-law shape, in contrast to the Schechter-like form of the underlying dark-matter halo mass function. We investigate a physical origin for the difference in these distributions by considering the impact of stochasticity induced by the processes that determine the quasar luminosity for a given host halo and redshift. We employ a conditional luminosity function and construct the relation between median quasar magnitude versus halo mass $M_{UV,\rm{c}}(M_{\rm{h}})$ with log-normal in luminosity scatter $Σ$, and duty-cycle $ε_{\rm{DC}}$, and focus on high redshift $z\gtrsim4$. We show that, in order to reproduce the observed QLF, the $Σ=0$ abundance matching requires all of the brightest quasars to be hosted in the rarest most massive dark-matter halos (with an increasing $M_{UV,\rm{c}}/M_{\rm{h}}$ in halo mass). Conversely, for $Σ>0$ the brightest quasars can be over-luminous outliers hosted in relatively common dark-matter halos. In this case, the median quasar magnitude versus halo mass relation, $M_{UV,\rm{c}}$, flattens at the high-end, as expected in self-regulated growth due to feedback. We sample the parameter space of $Σ$ and $ε_{\rm{DC}}$ and show that $M_{UV,\rm{c}}$ flattens above $M_{\rm{h}}\sim 10^{12}M_{\odot}$ for $ε_{\rm{DC}}<10^{-2}$. Models with $ε_{\rm{DC}}\sim1$ instead require a high mass threshold close to $M_{\rm{h}}\gtrsim10^{13}M_{\odot}$. We investigate the impact of $ε_{\rm{DC}}$ and $Σ$ on measurements of clustering and find there is no luminosity dependence on clustering for $Σ>0.3$, consistent with recent observations from Subaru HSC.
