The main goal of this thesis work is to find the links between star formation in galaxy bulges (mainly in the form of star-forming nuclear rings) and other properties of the host galaxy, such as the bar strength or the presence of sigma-drops. To do so we study galaxy non-axisymmetries and their side effects, such as dust lanes in bars. At the end

We have been monitoring the position of the very faint X-ray transient XTE J1728-295 (= IGR J17285-2922, ATel #2823, #2824, #2825) with the Faulkes Telescopes North and South throughout its outburst. Data were acquired on thirteen dates from 1st September until 28th October, mostly in I- band and R-band. Of the original seven stars detected with

While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear

Aims: We study how IMF sampling affects the ionizing flux and emission line spectra of low mass stellar clusters. Methods: We performed 2 × 106 Monte Carlo simulations of zero-age solar-metallicity stellar clusters covering the 20-106 M&sun; mass range. We study the distribution of cluster stellar masses, Mclus, ionizing fluxes, Q(H0), and

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