论文标题
自聚类集群以来，恒星形成的逐渐下降：新的运动学洞察力对环境淬火的速度为0.3 $ <z <$ <$ 1.1
A Gradual Decline of Star Formation since Cluster In-fall: New Kinematic Insights into Environmental Quenching at 0.3 $< z <$ 1.1
论文作者
论文摘要
星系居住的环境至关重要地塑造其恒星形成历史。我们研究了一个大型样本，该样本位于105个星系簇内，跨越了红移（$ 0.26 <z <1.13）$。星系簇很大（M $ _ {500} \ gtrsim 2 \ times10^{14} $ M $ _ {\ odot} $），并从SPT和ACT Sunyaev-Zel'dovich（sz）Surveys中均匀选择。对于成千上万个集群成员的光谱，我们使用星系在预计的相空间中的位置作为其下降时时间的代理，这比预计以群集以群集为中心的半径等数量的数量提供了更强的对环境的测量。我们发现明确的证据表明，基于4000 $Å$ Break，$ \ rm d _ {\ rm n} 4000 $的星系平均恒星种群逐渐增加（$ \ sim $ 0.71 $ \ pm $ 0.4 GYR），用于集群环境的时间。无论星系光度（微弱或明亮）和红移（低$ z $或高$ z $），发现这种环境淬火效果，尽管星系的确切星系年龄取决于固定环境效应的两个参数。这种系统的增加到$ \ rm d _ {\ rm n} 4000 $，其中落下代理会表明，由于较长的环境效应，例如RAM压力剥离和饥饿，因此早些时候将其积聚成宿主的星系较早淬火。与$ 1-3 $ gyr星系的典型动态时间尺度相比，在我们的样品星系中发现的年龄较小（$ \ sim $ 0.71 $ \ pm $ 0.4 GYR）似乎表明，诸如饥饿之类的缓慢环境过程是占主导地位的淬火途径。我们的结果为环境淬火效果提供了新的见解，这些效果跨越了宇宙时间的范围很大（$ \ sim 5.2 $ gyr，$ z = 0.26 $ - 1.13），并展示了使用运动学上衍生的fly时间代理的力量。
The environments where galaxies reside crucially shape their star formation histories. We investigate a large sample of 1626 cluster galaxies located within 105 galaxy clusters spanning a large range in redshift ($0.26 < z < 1.13)$. The galaxy clusters are massive (M$_{500} \gtrsim 2\times10^{14}$M$_{\odot}$), and are uniformly selected from the SPT and ACT Sunyaev-Zel'dovich (SZ) surveys. With spectra in-hand for thousands of cluster members, we use galaxies' position in projected phase space as a proxy for their in-fall times, which provides a more robust measurement of environment than quantities such as projected cluster-centric radius. We find clear evidence for a gradual age increase of the galaxy's mean stellar populations ($\sim$ 0.71 $\pm$ 0.4 Gyr based on a 4000 $Å$ break, $\rm D_{\rm n}4000$) with the time spent in the cluster environment. This environmental quenching effect is found regardless of galaxy luminosity (faint or bright) and redshift (low-$z$ or high-$z$), although the exact stellar age of galaxies depends on both parameters at fixed environmental effects. Such a systematic increase of $\rm D_{\rm n}4000$ with in-fall proxy would suggest that galaxies that were accreted into hosts earlier were quenched earlier, due to longer exposure to environmental effects such as ram pressure stripping and starvation. Compared to the typical dynamical time scales of $1-3$ Gyr of cluster galaxies, the relatively small age increase ($\sim$ 0.71 $\pm$ 0.4 Gyr) found in our sample galaxies seems to suggest that a slow environmental process such as starvation is the dominant quenching pathway. Our results provide new insights into environmental quenching effects spanning a large range in cosmic time ($\sim 5.2$ Gyr, $z=0.26$--1.13) and demonstrate the power of using a kinematically-derived in-fall time proxy.
