There is a long-standing debate why the Mn i 5394.7 Å line in the solar irradiance spectrum brightens more at higher activity than other photospheric lines. The claim that this is caused by spectral interlocking to chromospheric emission in the Mg ii h & k lines is disputed. In this paper we settle this issue, using classical one-dimensional

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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