论文标题
昏迷超集群不同环境中星系的年龄和金属性
Age and Metallicity of galaxies in different environments of the Coma supercluster
论文作者
论文摘要
我们分析了连续环境范围内的星系的光度加权年龄和金属性（Z），即昏迷超级集群中普遍存在的簇，细丝和空隙（$ \ sim 100 H^{ - 1} $ MPC）。具体来说，我们采用两个吸收线指数，H $β$和$ \ langle \ rm {fe} \ rangle $作为星系的年龄和金属性的示踪剂。我们发现，星系的出色阶段金属性随着恒星质量（$ m^*$）和环境的函数而增加。在细丝上，星系的金属性随距细丝脊柱的距离而变化，因此，靠近细丝中心的星系相对于其远离丝的1 MPC的金属性较低。中间大量星系的平均年龄（$ 10^{10} <m^*/m _ {\ odot} <10^{10.5} $）星系在统计上在不同的环境中的统计学差异很大，因此，在群集中的星系在群集中比细丝的年龄比1-1.5 gyr your $ y年轻，而$ n年轻，而$ gy则是$ $ gy $ $ $ $ $ y年轻。另一方面，巨大的星系（$ M^*/M _ {\ odot}> 10^{10.5} $）在簇和细丝中没有这种差异，但是它们在voids中的对应物在$ \ sim 0.5 $ 0.5 $ gyr中被发现年轻。然而，在固定年龄，星系的z在所有环境中都独立于其$ m^*$，除了最大的（$ m^*/m _ {\ odot} \ gtrsim 10^{10.7} $），最古老的星系（$ \ gtrsim 9 $ gyr），显示出与$ m m^$ a s显示的急剧下降。我们的结果支持一个场景，即通过从大规模宇宙网络中积聚较小的星系或原始气体来增长附近宇宙中的星系。
We analyse luminosity-weighted ages and metallicity (Z) of galaxies in a continuous range of environments, i.e. clusters, filaments and voids prevalent in the Coma supercluster ($\sim 100 h^{-1}$ Mpc). Specifically, we employ two absorption line indices, H$β$ and $\langle\rm{Fe}\rangle$ as tracers of age and metallicity of galaxies. We find that the stellar-phase metallicity of galaxies declines with increasing age as a function of stellar mass ($M^*$) as well as environment. On the filaments, metallicity of galaxies varies as a function of their distance from the spine of the filament, such that galaxies closer to the centre of the filaments have lower metallicity relative to their counterparts 1 Mpc away from it. The mean age of intermediate mass galaxies ($10^{10} < M^*/M_{\odot} < 10^{10.5}$) galaxies is statistically significantly different in different environments such that, the galaxies in clusters are older than the filament galaxies by 1-1.5 Gyr, while their counterparts in the voids are younger than filament galaxies by $\sim 1$ Gyr. The massive galaxies ($M^*/M_{\odot} > 10^{10.5}$), on the other hand show no such difference for the galaxies in clusters and filaments, but their counterparts in voids are found to be younger by $\sim 0.5$ Gyr. At fixed age however, Z of galaxies is independent of their $M^*$ in all environments, except the most massive ($M^*/M_{\odot} \gtrsim 10^{10.7}$), oldest galaxies ($\gtrsim 9$ Gyr) which show a sharp decline in their Z with $M^*$. Our results support a scenario where galaxies in the nearby Universe have grown by accreting smaller galaxies or primordial gas from the large-scale cosmic web.
