Přednášky a semináře
Semináře pořádáme nově s čtvrtletní periodou a s bohatším obsahem.
Příští seminářové odpoledne (od 13h)
23. 03. 2015
Solar spectropolarimetry from 0-D to 3-D geometry
Abstract: Scattering line polarization and the Hanle effect are among the most important mechanisms for diagnostics of the solar and stellar atmospheres. The fact that real stellar atmospheres are horizontally inhomogeneous makes the spectral synthesis and interpretation very challenging because the effect of thermodynamic fluctuations on spectral line polarization is entangled with the action of magnetic fields. This applies to the spatially resolved as well as to the averaged spectra. The necessary step towards the interpretation of such spectra is to study the line formation in sufficiently realistic 3D MHD models and to compare the synthetic spectra with observations. I'll present a brief overview of the relevant mechanisms involved in polarized spectral line formation and the recent progress in the field of 3D NLTE synthesis of polarized spectral lines.
23. 03. 2015
HI shells: why I find them interesting even after 20 years' acquaintance
Abstract: I will give an introduction to HI shells: what they are, where we can find them and why many members of our working group study them. I will focus on the connection between HI shells and other gaseous environment in the Galaxy and will deal with the importance of HI shells in the evolution of galaxies and the Galaxy.
23. 03. 2015
Exoplanets at Ondřejov
Abstract: Since 1995, when the first exoplanet was detected, this scientific field is rapidly developing. Nowadays, we are not only detecting the new worlds but we try to understand how did they evolve and how they do look like. The most recent topic is characterization of exoplanetary atmospheres. Current situation, advances and plans for the future development of the exoplantary research in Ondřejov will be presented.
23. 03. 2015
Bolide Žďár – First results of the recent precisely documented meteorite fall
Abstract: Instrumental observations of fireballs, especially those that can produce meteorites, are of great scientific interest and importance because meteorites provide us with a surviving physical record of the formation of our solar system, and a direct link to their parent asteroids. Last such event occurred over Czech Republic on December 9, 2014 at late dusk. It was
exceptionally well documented because cameras of the Czech part of the European Fireball Network provided us with 10 all-sky photographic images and 21 radiometric records. It enabled us to get very reliable and complex information about position, dynamics, photometry and absolute timing of this extraordinary event. The first results based on the analysis of the best available records and describing fireball trajectory, luminosity, dynamics, fragmentation, orbit, and impact position will be presented. Recovery of meteorites and their analysis will be also shortly mentioned.
Dále se konají menší tématické semináře jednotlivých oddělení:
Semináře slunečního oddělení
Vždy v úterý ve 13:00 (září–červen, s výjimkou úterků po celoústavním semináři) v zasedací místnosti slunečního oddělení pracoviště Ondřejov.
05/05/2015, 13:00
Solar 'tornadoes' observed by IRIS, THEMIS and other instruments
Semináře oddělení GPS
Obvykle v pondělí od 14 hod v přednáškové místnosti pracoviště Praha–Spořilov.
11. 05. 2015, 15:00
Testing the standard cold dark matter cosmological model
Abstract: The dual-dwarf-galaxy theorem, according to which two types of galaxies must exist and which must be true in the standard model of cosmology, appears to be ruled out by astronomical data: both types of dwarf galaxy, those with putative exotic dark matter and those known to not contain dark matter even if it were to exist, cannot be distinguished by observation. Furthermore, the arrangement of satellite galaxies in rotating disk-like vast near-polar structures around the Milky Way and Andromeda galaxies and the frequent occurrence of anisotropic flattened satellite populations around major galaxies, seem to very strongly support the conclusion that only one type of satellite dwarf galaxy exists, namely the type without dark matter. Also, the orbital decay implied by dynamical friction on the putative dark matter halos is not evident in interacting galaxies. Dynamically relevant cold or warm dark matter therefore seems not to be present. Instead and as suggested by Milgrom, scale-invariant dynamics is showing a new direction for understanding the astrophysics of galaxies. Galaxies are observed to be simple systems following laws that result from scale-invariant dynamics which do not emanate from the haphazard merging history of halos of exotic dark matter. As a result, the present-day cosmological description of galaxy formation and evolution appears to need major revision.
(Takes place at: Sporilov library)
Semináře stelárního oddělení
Ve čtvrtek od 14:00 v seminární místnosti stelárního oddělení.