论文标题
恒星后星系中不对称特征的中心浓度为$ z \ sim 0.8 $
Central Concentration of Asymmetric Features in Post-starburst Galaxies at $z \sim 0.8$
论文作者
论文摘要
我们在宇宙领域介绍了季后星系星系后星系（PSB）的形态分析（PSB）。我们将Ultraviolet拟合到中含物体的中红外多频段光度法，其中$ i <24 $来自COSMOS2020目录，并具有种群合成模型，假设恒星形成历史的非参数，零件的恒定功能，并选择了94个具有高度特定的星形（SSFR）的星系，则为$ 10^$ 10^$ y $ y y y y y y y y y y y超过$ 10^{-9.5} $ yr}在观察之前的Myr和最近321 Myr的SSFR较低的数量级。我们设计了一个新的非参数形态指数，该指数量化了不对称功能的浓度，$ c_ {a} $，并测量了它以及浓度$ c $和非对称$ c $ and bymmetry $ a $ a $ in Hubble Space望远镜/高级摄像机的监视$ i _ {\ rm f814w} $ - $ i _ {\ rm f814w} $ - 乐队图像。虽然相对较高的$ c $和low $ a $ a $ a $ a $ a $与静态星系相似，而不是恒星形成星系，但我们发现PSB的系统性更高的$ C_ {a} $的值比静态和恒星形成星系高； PSB的36％具有$ \ log {c_ {a}}> 0.8 $，而只有16％（2％）的静态（2％）星系显示出如此高的$ C_ {a} $ values。那些具有高$ C_ {a} $的PSB的总体不对称性相对较低，为$ a \ sim 0.1 $，但在中心附近显示出显着的不对称功能。 $ C_ {A} $的那些PSB的一部分随着321---1000 MYR的增加而增加，而不是在观察之前，而不是残留的恒星形成。这些结果及其高表面恒星质量密度表明，这些星系在最近的过去经历了核星爆，引起这种星爆的过程可能会导致通过快速的气体消耗，超新星/AGN反馈等通过快速的气体消耗来消除恒星形成。
We present morphological analyses of Post-starburst galaxies (PSBs) at $0.7<z<0.9$ in the COSMOS field. We fitted ultraviolet to mid-infrared multi-band photometry of objects with $i<24$ from COSMOS2020 catalogue with population synthesis models assuming non-parametric, piece-wise constant function of star formation history, and selected 94 those galaxies that have high specific star formation rates (SSFRs) of more than $10^{-9.5}$ yr$^{-1}$ in 321--1000 Myr before observation and an order of magnitude lower SSFRs within recent 321 Myr. We devised a new non-parametric morphological index which quantifies concentration of asymmetric features, $C_{A}$, and measured it as well as concentration $C$ and asymmetry $A$ on the Hubble Space Telescope/Advanced Camera for Surveys $I_{\rm F814W}$-band images. While relatively high $C$ and low $A$ values of PSBs are similar with those of quiescent galaxies rather than star-forming galaxies, we found that PSBs show systematically higher values of $C_{A}$ than both quiescent and star-forming galaxies; 36% of PSBs have $\log{C_{A}} > 0.8$, while only 16% (2%) of quiescent (star-forming) galaxies show such high $C_{A}$ values. Those PSBs with high $C_{A}$ have relatively low overall asymmetry of $A \sim 0.1$, but show remarkable asymmetric features near the centre. The fraction of those PSBs with high $C_{A}$ increases with increasing SSFR in 321--1000 Myr before observation rather than residual on-going star formation. These results and their high surface stellar mass densities suggest that those galaxies experienced a nuclear starburst in the recent past, and processes that cause such starbursts could lead to the quenching of star formation through rapid gas consumption, supernova/AGN feedback, and so on.
