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arXiv 2112.09720astro-ph.GA
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速度色散对盘分数、质光比和红移的弱依赖性：星系和黑洞演化的意义

The weak dependence of velocity dispersion on disk fractions, mass-to-light ratio and redshift: Implications for galaxy and black hole evolution

Christopher Marsden, Francesco Shankar, Mariangela Bernardi, Ravi Sheth, Hao Fu, Andrea Lapi

备注：
MNRAS accepted, 22 pages, 17 figures
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摘要：

速度色散（$σ$）是星系结构和演化的关键驱动力。在这里，我们提出了一个全面的半经验的方法来计算$σ$通过详细的牛仔裤建模假设一个常数和规模依赖的质光比$M^*/L$。通过与来自MaNGA的大样本局部星系的比较，发现两种模型都能再现Faber-Jackson（FJ）关系和$σ$对膨胀-总比$B/T$（对于$B/T\gtrsim 0.25$）的弱依赖性。$R\lesssim R_e$中的动力质量与恒星质量之比可以完全用$M^*/L$中的梯度来解释。然后，我们建立速度色散演化轨道$σ_{ap}[M^*,z]$（孔径内）沿主要祖暗物质晕分配恒星质量，有效半径和Sersic指数通过各种丰度匹配和经验动机的关系。我们发现：1）明确的证据，在$σ_{ap}[M^*,z]$缩小沿祖轨道; 2）在固定的恒星质量$σ\propto(1+z)^{0.2-0.3}$取决于存在或不存在的梯度，在$M^*/L$。我们提取$σ_{ap}[M^*,z]$从TNG 50流体动力学模拟，发现非常相似的结果，我们的模型与常数$M^*/L$。在$M^*/L$模型中，$R_e$中暗物质比例的增加倾向于使$σ_{ap}[M^*,z]$沿着$z \gtrsim 1$处的祖先变平，而$σ_{ap}[M^*,z]$在恒星梯度的存在下具有更陡峭的演化。然后，我们表明，合并和气体吸积的组合可能是负责恒定或随时间增加$σ_{ap}[M^*,z]$。最后，我们的$σ_{ap}[M^*,z]$与$z\lesssim 2$处几乎恒定且陡峭的$M_{bh}-σ$关系一致，黑洞质量来自$L_X-M^*$关系。

英文摘要：

Velocity dispersion ($σ$) is a key driver for galaxy structure and evolution. We here present a comprehensive semi-empirical approach to compute $σ$ via detailed Jeans modelling assuming both a constant and scale-dependent mass-to-light ratio $M^*/L$. We compare with a large sample of local galaxies from MaNGA and find that both models can reproduce the Faber-Jackson (FJ) relation and the weak dependence of $σ$ on bulge-to-total ratio $B/T$ (for $B/T\gtrsim 0.25$). The dynamical-to-stellar mass ratio within $R\lesssim R_e$ can be fully accounted for by a gradient in $M^*/L$. We then build velocity dispersion evolutionary tracks $σ_{ap}[M^*,z]$ (within an aperture) along the main progenitor dark matter haloes assigning stellar masses, effective radii and Sersic indices via a variety of abundance matching and empirically motivated relations. We find: 1) clear evidence for downsizing in $σ_{ap}[M^*,z]$ along the progenitor tracks; 2) at fixed stellar mass $σ\propto(1+z)^{0.2-0.3}$ depending on the presence or not of a gradient in $M^*/L$. We extract $σ_{ap}[M^*,z]$ from the TNG50 hydrodynamic simulation and find very similar results to our models with constant $M^*/L$. The increasing dark matter fraction within $R_e$ tends to flatten the $σ_{ap}[M^*,z]$ along the progenitors at $z \gtrsim 1$ in constant $M^*/L$ models, while $σ_{ap}[M^*,z]$ have a steeper evolution in the presence of a stellar gradient. We then show that a combination of mergers and gas accretion are likely responsible for the constant or increasing $σ_{ap}[M^*,z]$ with time. Finally, our $σ_{ap}[M^*,z]$ are consistent with a nearly constant and steep $M_{bh}-σ$ relation at $z\lesssim 2$, with black hole masses derived from the $L_X-M^*$ relation.

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