Wednesday Colloquium


"Precision vs accurate cosmology - how well do we know our Universe?"

Krzysztof Bolejko (Astrophysics Department, University of Oxford)


"Is the enigma of the pulsar radio emission solved?"

Georgi Melikidze (Institut of Astronomy, Zielona Góra)

Various possible physical processes able to provide the observed pulsar radio emission will be discussed. The successful mechanism should be able to generate the waves capable of (a) escaping from the pulsar magnetosphere and (b) satisfying the observational constraints. The main attention will be paid to the coherent curvature radiation which seems to be the most appropriate mechanism from the observational point of view. Also, it is the only possible mechanism that can operate at the low altitudes, where the wave generation region is most likely located. The sequence of physical processes taking place in the pulsar magnetosphere that result in generation of the observed radio-emission will be presented.


"Origin, Structure, and Evolution of Hot Jupiters and Super-Earths"

Doug Lin (Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing, China)

In the radial-velocity and transit searches, close-in planets are the first to be found. These planets are most likely formed at much larger distances from their host stars and migrated to their present-day location. I will discuss the implication of various recent discoveries including 1) the mass-period distribution of close-in planets, 2) their mass-radius relationship, 3) the mis-alignment of their orbital angular momentum vector and spin vector of their host stars, 4) their atmosphere 5) the dynamical architecture of closely-packed multi-planet systems, and 6) their presence around binary stars. I will discuss relevant and dominant physical processes which may have led to these features. Based on these theoretical consideration and population synthesis models, we suggest that 1) sequential core accretion is the dominant mode of planet formation process, 2) planets have considerable mobility, 3) habitable planets are common, and 4) dynamical evolution of planetary systems is an ongoing process.


"Formation of dwarf spheroidal galaxies in the Local Group"

Ewa Łokas (Copernicus Astronomical Center, Warsaw)

I will review two scenarios for the formation of dwarf spheroidal galaxies in the Local Group: the tidal stirring model and formation by mergers. In both cases the progenitors are disky dwarfs embedded in dark matter halos. Both scenarios produce objects with observational features remarkably similar to the classical dSph satellites of the Milky Way.