Seminarium Zakładu Astrofizyki

Thousands of extrasolar planets have been discovered up to date. Although many of the known exoplanets do not resemble those in our solar system, they have one thing in common - they all orbit a star. However, theories of planet formation and evolution predict the existence of free-floating planets, gravitationally unattached to any star.

Certain active galaxies produce powerful jets with relativistic velocities, which emit highly anisotropic non-thermal radiation. In case that a jet is directed towards an observer, the observed luminosity of its radiation exceeds significantly the luminosity of the host galaxy; such objects are called blazars. Observations of blazars indicate very efficient mechanisms of energy dissipation and non-thermal particle acceleration. The inner sections of jets are most likely relativistically magnetised, i.e., the magnetic energy density exceeds the rest-mass energy density of the matter.

The majority of the stars in the local Universe belong to massive, red, spheroidal, old galaxies that died several billion years ago, ceasing their active formation of new stars. In our current view, these galaxies experienced an intense burst of growth immediately followed by a sudden death early in the Universe, so that we routinely observe a numerous population of such dead cosmic giants already in place 10 Gyr ago at z~2, comfortably reproduced by the most recent galaxy formation models and simulations.