The fractions and dimension of bars, rings and lenses are studied in the Near-IR S0 galaxy Survey (NIRS0S). We find evidence that multiple lenses in some barred S0s are related to bar resonances in a similar manner as the inner and outer rings, for which the outer/inner length ratio 2. Inner lenses in the non-barred galaxies normalized to galaxy diameter are clearly smaller than those in the barred systems. Interestingly, these small lenses in the non-barred galaxies have similar sizes as barlenses (lens-like structures embedded in a bar), and therefore might actually be barlenses in former barred galaxies, in which the outer, more elongated bar component, has been destroyed. We also find that fully developed inner lenses are on average a factor 1.3 larger than bars, whereas inner rings have similar sizes as bars. The fraction of inner lenses is found to be constant in all family classes (A, AB, B). Nuclear bars appear most frequently among the weakly barred (AB) galaxies, which is consistent with the theoretical models by Maciejewski & Athanassoula (2008). Similar sized bars as the nuclear bars were detected in seven 'non-barred' S0s. Galaxy luminosity does not uniquely define the sizes of bars or bar-related structures, neither is there any upper limit in galaxy luminosity for bar formation. Although all the family classes cover the same range of galaxy luminosity, the non-barred (A) galaxies are on average 0.6 mag brighter than the strongly barred (B) systems. Overall, our results are consistent with the idea that bars play an important role in the formation of the structure components of galaxies. The fact that multiple lenses are common in S0s, and that at least the inner lenses can have very old stellar populations, implies that the last destructive merger, or major gas accretion event, must have taken place at a fairly high redshift.
Rotation of classical bulges during secular evolution of barred galaxies
棒驱动的长期演化在改变盘星系的形态和运动学方面起着关键作用，导致快速旋转的方形/花生状凸起的形成。如果这些盘状星系也有一个先前存在的经典核球，那么长期演化将如何影响经典核球，以及观测性质。我们首先研究的酒吧和一个预先存在的非旋转的低质量的经典凸起，如可能存在于像银河系的星系的共同演化。它与N体模拟表明，在长期的演变过程中，这样的凸起可以获得显着的角动量发出的酒吧通过共振和随机轨道。因此，它变成了一个圆柱形旋转，各向异性和三轴物体，嵌入通过磁盘不稳定性形成的快速旋转的方形凸起中（Saha等人，2012）。复合的方形/花生状凸起也以圆柱形旋转。然后，我们表明，酒吧的增长只略有依赖于预先存在的经典凸起的旋转特性。对于最初旋转的小的经典凸起，由此产生的复合方形/花生状凸起中的圆柱旋转延伸到较低的高度（Saha & Gerhard 2012）。更大质量的经典凸起也获得了由棒发射的角动量，在大约4 Gyrs内引起了令人惊讶的大旋转支持（Saha等人准备）。
Evolution along the sequence of S0 Hubble types induced by dry minor mergers. II - Bulge-disk coupling in the photometric relations through merger-induced internal secular evolution
The two-phase formation history of spiral galaxies traced by the cosmic evolution of the bar fraction
我们研究了星系棒的演化和与磁盘和球体形成的放大宇宙学模拟的样本中的链接。我们的模拟样本集中在现今恒星质量在10^10-10^11兆太阳范围内的星系，在场和松散的群环境中，具有各种各样的质量增长历史。在我们的模型中，在z>1.5时，现在螺旋的祖先几乎不存在条形，它们仍然很罕见，而且通常太弱而无法观察到z~1。在这一特征时期之后，可观测到的强条的比例迅速上升，80%的旋涡星系中存在条，其中三分之二在z<0.5时很容易观测到。这与观测到的棒分数的红移演化是定量一致的。我们的模型预测，随着红移的增加，酒吧分数的减少应该继续与可观察到的酒吧1的分数<10-15% in disk galaxies at z>。我们的模型还预测了较低质量星系中稍后的酒吧形成，与现有数据一致。我们发现，酒吧形成的特征时代，即红移z~0.8-1，对应的时代，今天的螺旋获得其磁盘为主的形态。在更高的红移，盘倾向于被合并和引力不稳定性迅速破坏，很少发展出明显的棒。棒形成时期对应于螺旋星系形成的早期“剧烈”阶段（z>1）和晚期“长期”阶段（z<0.8）之间的过渡。在长期阶段，酒吧的存在大大有助于增长的隆起，但隆起的质量预算仍然占主导地位的合并，相互作用和磁盘的不稳定性在高红移的贡献。z>1时的早期棒通常是短暂的，而z<1时形成的大多数棒一直持续到z=0，晚期宇宙学气体的注入是维持其中一些棒的必要条…
