Abridged. The feedback between massive stars and the interstellar medium is one of the most important processes in the evolution of dwarf galaxies. This interaction results in numerous neutral and ionised gas structures that have been found both in the disc and in the halo of these galaxies. However, their origin and fate are still poorly understood. We here present new HI and optical data of two nearby irregular dwarf galaxies: IC 4662 and NGC 5408. The HI line data were obtained with the ATCA and are part of the Local Volume HI Survey. They are complemented by optical images and spectroscopic data obtained with the ESO NTT and the ESO 3.6m telescope. Our main aim is to study the kinematics of the neutral and ionised gas components in order to search for outflowing gas structures and to make predictions about their fate. We find the HI gas envelopes of both galaxies to extend well beyond the optical discs. The optical disc is embedded into the central HI maximum in both galaxies. However, higher resolution HI maps show that the HI intensity peaks are typically offset from the prominent HII regions. While NGC 5408 shows a fairly regular HI velocity field, which allows us to derive a rotation curve, IC 4662 reveals a rather twisted HI velocity field, possibly caused by a recent merger event. We detect outflows with velocities between 20 and 60 km/s in our Halpha spectra of both galaxies, sometimes with HI counterparts of similar velocity. We suggest the existence of expanding superbubbles, especially in NGC 5408. This is also supported by the detection of FWHMs as high as 70 km/s in Halpha. In case of NGC 5408, we compare our results with the escape velocity of the galaxy, which shows that the measured expansion velocities are in all cases too low to allow the gas to escape from the gravitational potential of NGC 5408. This result is consistent with studies of other dwarf galaxies.
X-ray narrow emission lines from the nuclear region of NGC 1365
NGC 1365是一个塞弗特2星系，在它的核区域有一个星暴环。在这项工作中，我们研究了XMM反射光栅光谱仪（RGS）从2012-13年的四次观测，2007年的三次观测和2004年的两次观测中获得的数据NGC 1365。我们通过XMM RGS对可见的窄线发射气体进行了分析，并将2012-13光谱与已经发表的2004-07光谱进行了比较。该源通常在软X射线带内被吸收，典型的中性柱密度>1.5 x 10 $^{23}$ cm $^{-2}$，并且在我们调查的9个观测中只有1个观测显示出足够低的吸收，使得连续谱出现在软X射线中。我们将2004-07年的所有观测结果进行叠加，并将2012-13年的四个观测结果中的三个分别进行叠加，分别分析吸收较少的观测结果。我们首先使用高斯分布代表的窄线发射光谱模型。我们适合物理动机的模型，2012-13堆叠的光谱，碰撞电离组件代表星暴发射和光电离线发射模型代表活动星系核线发射。碰撞和光电离发射线模型拟合在一起的物理连续和吸收模型的顶部。NGC 1365的X射线窄发射线光谱很好地代表了两个碰撞电离和三个光电离阶段的发射气体，所有高于太阳氮丰度的组合。这个物理模型与2012-13年的叠加光谱相吻合，也与2004-07年的叠加光谱吻合得很好，而不会改变发射气体相的任何特征。我们2004-07年的结果与之前使用这些数据的发射线工作一致，在这个和2012-13年的叠…
