Seminář se koná každé úterý v 10:40 v posluchárně ÚTF MFF UK
v 10. patře katedrové budovy v Tróji, V Holešovičkách 2, Praha 8
Over the last ten years, a population of so-called "Ultra Diffuse Galaxies" has been uncovered which was not predicted by cosmological models. These systems are the same size as the Milky Way but a thousand times fainter, with their total mass still a matter of contention. I will present the results from Arecibo surveys regarding the detection of several UDGs in neutral hydrogen emission, allowing estimates of their dynamical mass. I will also examine how these compare to other, similar objects of extremely low luminosity dubbed `blue blobs', which have been proposed to result from gas stripping in galaxy clusters, reviewing whether clusters are likely to be responsible for the creation or destruction of such objects, or whether both processes might be in effect.
Internal and external processes such as mantle convection, deglaciation, and atmospheric circulation force planetary bodies to move as a whole relative to their rotation axis. The rotation poles of planets and moons thus wander on their surfaces, as shown by paleomagnetic, astrometric, or geological observations (true polar wander). Due to the extremely slow rotation of Venus and its near absence of a rotational bulge, true polar wander on Venus was thought to be anomalous - the rotation pole was considered to follow a circular path on the planet's surface (wobble). Here, we argue instead that true polar wander on Venus proceeds similarly to that of fast rotating planets such as Earth or Mars, and derive a scaling law for the offset between the rotation and figure poles during true polar wander.
Professor Werner Espe (1899 Elbing, Prussia – 1970 Bratislava), a nearly forgotten figure of German and Czechoslovak history, was a student of physics in Berlin around 1920, who then played a key role in advancing vacuum technologies, electrovacuum technology, and electronics in the Czechoslovak Republic after 1945. Let us reconstruct his personal life story throughout the turbulent 20th century, as well as the network of his teachers, colleagues, and students, and his own substantial scientific research.
Jiří Horáček David Heyrovský