Properties of Bars and Bulges in the Hubble Sequence
Properties of Bars and Bulges in the Hubble Sequence
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DOI：
10.1111/j.1365-2966.2007.12299.x
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发表时间：
2007-02
影响因子：
4.8
通讯作者：
E. Laurikainen;H. Salo;R. Buta;J. Knapen;J. Knapen
中科院分区：
文献类型：
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作者：
E. Laurikainen;H. Salo;R. Buta;J. Knapen;J. Knapen
本文根据对216个盘星系（分别来自NIRS和OSUBGS巡天的S_0和螺旋星系）的分析，讨论了哈勃序列中棒星系和球星系的性质。为此目的，我们已经收集了，并在必要时完成了我们以前分别对早期和晚期类型进行的各种分析。我们发现强有力的光度和运动学证据的pseudobulges在S 0-S 0/a星系：他们的凸起平均相当指数，内盘是常见的（在56%），并在许多星系的凸起旋转支持。如果这些伪球候选者是由盘中的星星以类似于螺旋的方式形成的，那么在S 0 s这样的贫气体星系中这将很难理解。一个更可能的解释是，在早期型星系的pseudobulges是酒吧相关的结构，连接到酒吧的演变，这一解释是支持我们的傅立叶分析和结构分解。发现早型星系中的棒具有许多演化系统的特征：（1）具有平顶/双峰傅立叶振幅轮廓，（2）棒具有典型的尖锐外截止，（3）振幅轮廓中出现高傅立叶模，（4）许多棒还具有柄型形态。我们使用四个棒强度指标Qg、A2、fbar和棒长度来显示不同哈勃类型仓中棒强度的分布，这有望为理解棒的演化机制提供重要线索。
Properties of bars and bulges in the Hubble sequence are discussed, based on the analysis of 216 disk galaxies (S0s and spirals from NIRS0S and OSUBGS surveys, respectively). For that purpose we have collected together, and completed when necessary, the various analysis we have previously made separately for early and late types. We find strong photometric and kinematic evidence of pseudobulges in the S0-S0/a galaxies: their bulges are on average fairly exponential, inner disks are common (in 56%), and in many of the galaxies the bulges are rotationally supported. This would be difficult to understand in such gas poor galaxies as in S0s, i f these pseudobulge candidates were formed by star formation in the disk in a a similar manner as in spirals. A more likely explanation is that pseudobulges in the early-type galaxies are bar-related structures, connected to the evolution of bars, which interpretation is supported by our Fourier analysis and structural decompositions. Bars in the early-type galaxies are found to have many characteristics of evolved systems: (1) they have flat-top/double peaked Fourier amplitude profiles, (2) bars have typically sharp outer cut-offs, (3) the higher Fourier modes appear in the amplitude profiles, and (4) many bars have also ansae-type morphologies. We show the distributions of bar strength in different Hubble type bins using four bar strength indicators, Qg, A2, fbar and the bar length, which are expected to give important clues for understanding the mechanism of how bars evolve.