We study the evolution of initially spherical satellites of a galaxy that resembles the Milky Way using N-Body simulations. The initial satellites come from a Plummer sphere model with 10^6 particles, they are dark matter free and have typical masses of 10^7 - 10^9~M_&sun;. The satellite is bounded by a galactic potential: A Miyamoto-Nagai

Years ago we have compiled all the available optical data in the literature to build a comprehensive classification of the low-ionization structures (LIS), as knots, jets and jet-like structures in planetary nebulae (PNe). This classification highlighted a number of questions that 6 years later still remain open, such as, what is the role of

We present deep near-infrared Ks -band Anglo-Australian Telescope Infrared Imager and Spectrograph observations of a selected sample of nearby barred spiral galaxies, including some with the strongest known bars. The sample covers a range of Hubble types from SB0- to SBc. The goal is to determine if the torque strengths of the spirals correlate

Although the stellar initial mass function (IMF) has only been directly determined in star clusters, it has been manifoldly applied on galaxy-wide scales. But taking the clustered nature of star formation into account the galaxy-wide IMF is constructed by adding all IMFs of all young star clusters leading to an integrated galactic initial mass

High-resolution imaging observations from the Hinode spacecraft in the Ca II H line are employed to study the dynamics of the chromosphere above a sunspot. We find that umbral flashes and other brightenings produced by the oscillation are extremely rich in fine structure, even beyond the resolving limit of our observations (0farcs22). The umbra is

The observations of NGC 1997 and OHSC 28 were performed using the Tektronix 2K CCD #3 at the 0.9m telescope at the Cerro Tololo Inter-American Observatory (CTIO) on 1997 December 20 and 23, respectively, while those of NGC 1697, SL 133 and SL 663 were obtained with the Danish Faint Object Spectrograph and Camera (DFOSC) on the 1.54m Danish