论文标题
重建大型星系组装。 I：祖细胞效应在观察到的静态星系的特性中的重要性
Reconstructing the Assembly of Massive Galaxies. I: The Importance of the Progenitor Effect in the Observed Properties of Quiescent Galaxies at $z\approx 2$
论文作者
论文摘要
我们研究了Redshift $ \ langle z_ {obs} \ rangle \ langle \ langle \ langle \ langle \ oft 2 $，与Stellar Mass $ \ log M _*\ ge10.3 $一起选择了361个静态星系（QGS）的形态和恒星形成历史（SFH）之间的关系。利用涵盖剩下的紫外线到NIR光谱范围（$ \ of40 $ bands）的全型光度法，我们用完全贝叶斯SED拟合代码前景重建了星系的非参数SFH。我们发现，在$ z_ {obs} $上观察到的半光半径$ r_e $取决于星系的形成红移，$ z_ {form} $，并且这种关系取决于恒星质量。在$ \ log m _*<11 $时，这种关系与$ r_e \ propto（1+z_ {form}}）^{ - 1} $一致，这与期望星系的中央密度取决于形成时宇宙密度的期望，即“前代效应”。在$ \ log m _*> 11 $时，$ r_e $和$ z_ {form} $之间的关系变平，这表明合并对于淬火后更大的星系的尺寸增长变得越来越重要。我们还发现，$ z_ {form} $和星系紧凑度之间的关系类似地取决于恒星质量。虽然对于$ \ log m _*> 11 $的QGS没有明确的趋势，但下面形成的低质量QG，即具有较大的$ z_ {form} $，具有较大的中央恒星质量表面密度，均在$ r_e $ $ $ r_e $（$ n $（$σ_e$）和中央1 kpc（$ nectran）中（$ nectral 1 kpc）（$ necter） $ m_ {1kpc}/m _*$，中央1 kpc中的分数质量。但是，如果$ z_ {form} $与紧凑度之间的这些趋势基本上消失，则如果祖细胞效应通过$ z_ {form form} $的宇宙密度归一化，从而消除了祖细胞效应。我们的发现突出了在试图推断出它们内在的结构进化之前重建星系SFH的重要性。
We study the relationship between the morphology and star formation history (SFH) of 361 quiescent galaxies (QGs) at redshift $\langle z_{obs}\rangle\approx 2$, with stellar mass $\log M_*\ge10.3$, selected with the UVJ technique. Taking advantage of panchromatic photometry covering the rest-frame UV-to-NIR spectral range ($\approx40$ bands), we reconstruct the non-parametric SFH of the galaxies with the fully Bayesian SED fitting code Prospector. We find that the half-light radius $R_e$, observed at $z_{obs}$, depends on the formation redshift of the galaxies, $z_{form}$, and that this relationship depends on stellar mass. At $\log M_*<11$, the relationship is consistent with $R_e\propto(1+z_{form})^{-1}$, in line with the expectation that the galaxies' central density depends on the cosmic density at the time of their formation, i.e. the "progenitor effect". At $\log M_*>11$, the relationship between $R_e$ and $z_{form}$ flattens, suggesting that mergers become increasingly important for the size growth of more massive galaxies after they quenched. We also find that the relationship between $z_{form}$ and galaxy compactness similarly depends on stellar mass. While no clear trend is observed for QGs with $\log M_*>11$, lower-mass QGs that formed earlier, i.e. with larger $z_{form}$, have larger central stellar mass surface densities, both within the $R_e$ ($Σ_e$) and central 1 kpc ($Σ_{1kpc}$), and also larger $M_{1kpc}/M_*$, the fractional mass within the central 1 kpc. These trends between $z_{form}$ and compactness, however, essentially disappear, if the progenitor effect is removed by normalizing the stellar density with the cosmic density at $z_{form}$. Our findings highlight the importance of reconstructing the SFH of galaxies before attempting to infer their intrinsic structural evolution.
