倾斜和扭曲光盘内倾斜的暗物质晕预测从数值和半解析研究。在本文中，我们使用深度成像来证明在真实星系中可能存在倾斜的外部结构。我们考虑两个SB 0的边缘上的星系，NGC 4469和NGC 4452，这表现出明显的倾斜外盘相对于内部结构。在NGC 4469中，该结构具有盒状形状，相对于内部盘倾斜$Δ$ PA $\approx$ 3 $^{\circ}$，而NGC 4452具有盘状外部结构，$Δ$ PA $\approx$ 6 $^{\circ}$。尽管形状不同，这两种结构的表面亮度曲线接近指数，并作出很大的贡献（$\sim30$ %）的总星系光度。在NGC 4452的情况下，我们建议，它的倾斜盘可能源于以前的快速潮汐遇到（可能与IC 3381）。对于NGC 4469，一个合理的解释也可能是星系的骚扰，这导致了倾斜甚至翻滚的暗物质晕。一个不太可能的可能性是几个Gyr前富含气体的卫星的吸积。新的深层观测可能会揭示更多这样的星系，特别是在星系团中具有倾斜的外部结构。我们还考虑了文献中提到的星系，其中一个中心组件（一个酒吧或凸起）相对于恒星盘倾斜。根据我们的数值模拟，这种观察到的“倾斜”的凸起/酒吧的一个合理的解释是投影效应，由于不完全边缘上的取向的星系加上倾斜角的三轴凸起/酒吧。
英文摘要：
Tilted and warped discs inside tilted dark matter haloes are predicted from numerical and semi-analytical studies. In this paper, we use deep imaging to demonstrate the likely existence of tilted outer structures in real galaxies. We consider two SB0 edge-on galaxies, NGC4469 and NGC4452, which exhibit apparent tilted outer discs with respect to the inner structure. In NGC4469, this structure has a boxy shape, inclined by $Δ$PA$\approx$3$^{\circ}$ with respect to the inner disc, whereas NGC4452 harbours a discy outer structure with $Δ$PA$\approx$6$^{\circ}$. In spite of the different shapes, both structures have surface brightness profiles close to exponential and make a large contribution ($\sim30$%) to the total galaxy luminosity. In the case of NGC4452, we propose that its tilted disc likely originates from a former fast tidal encounter (probably with IC3381). For NGC4469, a plausible explanation may also be galaxy harassment, which resulted in a tilted or even a tumbling dark matter halo. A less likely possibility is accretion of gas-rich satellites several Gyr ago. New deep observations may potentially reveal more such galaxies with tilted outer structures, especially in clusters. We also consider galaxies, mentioned in the literature, where a central component (a bar or a bulge) is tilted with respect to the stellar disc. According to our numerical simulations, one of the plausible explanations of such observed "tilts" of the bulge/bar is a projection effect due to a not exactly edge-on orientation of the galaxy coupled with a skew angle of the triaxial bulge/bar.
Star formation in the outer regions of the early type galaxy NGC 4203
NGC 4203是一个邻近的早型星系，被一个非常大的低柱密度HI盘所包围。本文利用紫外、深空光学成像和红外观测数据研究了NGC 4203气体盘的恒星形成效率。我们确认HI盘由两个不同的组成部分：一个内部的恒星形成环，半径从$\sim$ 1到$\sim$ 3 R $_{eff}$，和一个外部盘。外环的质量是内环的9倍。在HI内环的位置，我们在深$g'-r'$图像和8 $μ$ m $Spitzer$ -IRAC图像中都检测到螺旋状结构，其半径延伸至$\sim$ 3 R $_{eff}$。这两种气体成分有不同的恒星形成效率，可能是由于不同的金属含量和尘埃含量。内部组成部分的恒星形成效率与晚型星系的内部区域非常相似。虽然外层的恒星形成效率很低，但它与螺旋星系和矮星的外层区域相似。我们认为，这些差异可以解释与不同的气体来源的两个组件，如恒星质量损失的内部HI环和吸积从星系间介质（IGM）的外部HI盘。外HI盘的低水平恒星形成效率不足以改变NGC 4203的形态，使得HI气体的耗尽时间太长。
Elemental Abundances in M31: A Comparative Analysis of Iron and Alpha Element Abundances in the Outer Disk, Giant Stellar Stream, and Inner Halo of M31
The Inner and Outer Shock Layers of Bow Shocks in Cataclysmic Variables
Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences（波兰科学院尼古拉·哥白尼天文学中心）；School of Physics and Astronomy, University of Southampton（南安普顿大学物理与天文学院）；Centre for Extragalactic Astronomy, Department of Physics, Durham University（达勒姆大学物理系河外天文研究中心）；INAF-Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Astronomy and Astrophysics Group, Department of Physics, University of Warwick（华威大学物理系天文与天体物理学组）；Department of Space, Earth and Environment, Chalmers University of Technology（查尔姆斯理工大学空间、地球与环境系）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所（西班牙高等科学研究理事会））；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究研究所）
The interface between the outer heliosphere and the inner lism: Morphology of the local interstellar cloud, its hydrogen hole, stromgren shells, and $^{60}$Fe accretion
