The stellar mass Fundamental Plane: the virial relation and a very thin plane for slow rotators
The stellar mass Fundamental Plane: the virial relation and a very thin plane for slow rotators
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DOI：
10.1093/mnras/staa1064
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发表时间：
2020-04
影响因子：
4.8
通讯作者：
M. Bernardi;H. Sánchez;B. Margalef-Bentabol;F. Nikakhtar;R. Sheth
中科院分区：
文献类型：
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作者：
M. Bernardi;H. Sánchez;B. Margalef-Bentabol;F. Nikakhtar;R. Sheth
早期类型星系--慢转和快转椭圆体(E-SRS和E-FRS)和SOS/透镜星系--在半光半径、封闭表面亮度和速度色散的空间中定义了一个基面(FP)。由于$i_e$和$\sigma_e$是与距离无关的测量值，因此FP的厚度通常用$i_e$和$\sigma_e$用于估计大小$R_e$的精度来表示。我们发现：1)FP的厚度强烈地依赖于形态。如果样本只包含E-SR，则在$R_e$中观察到的散布是$\sim 16$，其中只有$\sim 9$是固有的。去掉具有$M*<；10^{11}M_\odot$的星系，观测到的散射进一步减少到$\sim 13\$($\sim 4\$本征)。如果添加E-FRS和SOS，则观察到的散射增加到文献中通常引用的$sim 2 5$。如果用观测到的协方差矩阵的特征向量来定义FP，那么E-SRS又定义了一个异常薄的FP，其本征散射值仅为$5，与平面垂直。2)FP中的结构最容易理解为：$i_e$和$\sigma_e$几乎是独立的，而$R_e-i_e$和$R_e-\sigma_e$几乎是相等和相反的。3)如果FP的系数不同于与维里定理有关的系数，则该平面被称为“倾斜的”。如果我们将$i_e$乘以全球恒星质量与光比$M_*/L$，并且我们使用Seric光度学来考虑整个群体的非同质性，那么所得到的恒星质量FP的倾斜度较小。自我一致地核算$M_*/L$梯度将改变倾斜度。我们目前看到的倾斜表明，将重子转化为恒星的效率随着恒星表面亮度的增加而增加和/或暗物质分数减少。
Early-type galaxies -- slow and fast rotating ellipticals (E-SRs and E-FRs) and S0s/lenticulars -- define a Fundamental Plane (FP) in the space of half-light radius $R_e$, enclosed surface brightness $I_e$ and velocity dispersion $\sigma_e$. Since $I_e$ and $\sigma_e$ are distance-independent measurements, the thickness of the FP is often expressed in terms of the accuracy with which $I_e$ and $\sigma_e$ can be used to estimate sizes $R_e$. We show that: 1) The thickness of the FP depends strongly on morphology. If the sample only includes E-SRs, then the observed scatter in $R_e$ is $\sim 16\%$, of which only $\sim 9\%$ is intrinsic. Removing galaxies with $M_*<10^{11}M_\odot$ further reduces the observed scatter to $\sim 13\%$ ($\sim 4\%$ intrinsic). The observed scatter increases to the $\sim 25\%$ usually quoted in the literature if E-FRs and S0s are added. If the FP is defined using the eigenvectors of the covariance matrix of the observables, then the E-SRs again define an exceptionally thin FP, with intrinsic scatter of only $5\%$ orthogonal to the plane. 2) The structure within the FP is most easily understood as arising from the fact that $I_e$ and $\sigma_e$ are nearly independent, whereas the $R_e-I_e$ and $R_e-\sigma_e$ correlations are nearly equal and opposite. 3) If the coefficients of the FP differ from those associated with the virial theorem the plane is said to be `tilted'. If we multiply $I_e$ by the global stellar mass-to-light ratio $M_*/L$ and we account for non-homology across the population by using Sersic photometry, then the resulting stellar mass FP is less tilted. Accounting self-consistently for $M_*/L$ gradients will change the tilt. The tilt we currently see suggests that the efficiency of turning baryons into stars increases and/or the dark matter fraction decreases as stellar surface brightness increases.