Experiences with the use of the local correlation tracking method when studying large-scale velocity fields
Švanda, Michal; Sobotka, Michal; Klvaňa, Miroslav
2005 - English We verify the reliability of the method recently used for the calculation of the large-scale velocity fields on synthetic dopplergrams obtained by a very simple numerical simulation of the supergranular pattern. A series of synthetic dopplergrams was stretched by the known vector field and the LCT was applied. The results were compared with the original vector field. Applying the LCT method on synthetic data we got an important experience in the behaviour of this method when used on full-disc dopplergrams. On the basis of the described tests we assume that the use of LCT on full-disc dopplergrams provides sufficiently reliable results, so that method could be used for mapping the large-scale velocities with resolution 60" and an accuracy 10 m/s. V práci předkládáme testy metody použité v předchozích pracech pro výpočty velkorozměrových rychlostních polí na syntetických dopplergramech získaných jednoduchou simulací supergranulárních struktur. Série syntetických dopplergramů byla deformována známým vektorovým polem, na data byla posléze aplikována metoda LCT. Porovnáním získaných výsledků s modelovými daty jsme získali důležité informace o chování metody při použití na celodiskových dopplergramech. Na základě testů můžeme považoat LCT metodu za dostatečně stabilní při výpočtu rychlostních polí s rozlišením 60", přičemž absolutní chyba výsledků činí 10 m/s. Keywords: solar photosphere; velocity fields Available at various institutes of the ASCR Experiences with the use of the local correlation tracking method when studying large-scale velocity fields

We verify the reliability of the method recently used for the calculation of the large-scale velocity fields on synthetic dopplergrams obtained by a very simple numerical simulation of the ...

Švanda, Michal; Sobotka, Michal; Klvaňa, Miroslav
Astronomický ústav, 2005

Six-year cycles of the Earth rotation and gravity
Chapanov, Y.; Vondrák, Jan; Gorshkov, V.; Ron, Cyril
2005 - English Six-year cycles of pseudo-periodical oscillations are discovered in the series of astrometrical observations of the latitude and universal time, tidal observations and Earth rotation series. Jsou nalezeny šestileté cykly pseudo-periodických variací v astrometrickém pozorování šířky a světového času, slapových pozorováních a v sériích rotace Země. Keywords: Earth rotation; gravity Available at various institutes of the ASCR Six-year cycles of the Earth rotation and gravity

Six-year cycles of pseudo-periodical oscillations are discovered in the series of astrometrical observations of the latitude and universal time, tidal observations and Earth rotation series....

Chapanov, Y.; Vondrák, Jan; Gorshkov, V.; Ron, Cyril
Astronomický ústav, 2005

An introduction to relativistic magnetohydrodynamics I
Karas, Vladimír
2005 - English The aim of this lecture is to present important basic relations of relativistic magnetohydrodynamics. Cílem této přednášky je podat důležité základní vztahy relativistické magnetohydrodynamiky. Keywords: magnetoydrodynamics Available at various institutes of the ASCR An introduction to relativistic magnetohydrodynamics I

The aim of this lecture is to present important basic relations of relativistic magnetohydrodynamics.

Karas, Vladimír
Astronomický ústav, 2005

On polarization of light scattered on hot electron clouds
Horák, Jiří
2005 - English We explore polarization of radiation of hot electron clouds. Studujeme polarizaci záření horkých elektronových oblaků. Keywords: polarization Available at various institutes of the ASCR On polarization of light scattered on hot electron clouds

We explore polarization of radiation of hot electron clouds.

Horák, Jiří
Astronomický ústav, 2005

Accuracy assessment of gravity field models by independent satellite crossover altimetry
Klokočník, Jaroslav; Wagner, C. A.; Kostelecký, J.
2005 - English A continuous progress in the Earth gravity field modeling requires some refinements in their accuracy assessments. The method based on latitude lumped coefficients, which makes use of satellite crossover altimetry data (independent of the tested gravity models) has been developed in years 1992 - 2000. It was applied on various gravity models, recently on EIGEN IS, which already includes data from the CHAMP mission. For the first time, EIGEN IS model has degree-dependent calibration factors and we tested and confirm that their choice is a right one. Přehled metod testování přesnosti v současné době publikovaných modelů tíhového pole Země pomocí diferenciální altimetrie s křížícími se body pro jednu a dvě družice. Keywords: GRIM5-S1 Available at various institutes of the ASCR Accuracy assessment of gravity field models by independent satellite crossover altimetry

A continuous progress in the Earth gravity field modeling requires some refinements in their accuracy assessments. The method based on latitude lumped coefficients, which makes use of satellite ...

Klokočník, Jaroslav; Wagner, C. A.; Kostelecký, J.
Astronomický ústav, 2005

Some aspects of the Stoermer problem within strong gravitational field
Schovancová, J.; Šubr, L.; Karas, Vladimír; Stuchlík, Z.; Kovář, J.
2005 - English We study halo orbits in strong gravitational fields. Studujeme halo orbity v silných gravitačních polích. Keywords: gravitation Available at various institutes of the ASCR Some aspects of the Stoermer problem within strong gravitational field

We study halo orbits in strong gravitational fields.

Schovancová, J.; Šubr, L.; Karas, Vladimír; Stuchlík, Z.; Kovář, J.
Astronomický ústav, 2005

Morphology and kinematics of narrow-line regions in Seyfert galaxies
Stoklasová, Ivana; Jungwiert, Bruno; Ferruit, P.
2004 - English Available at various institutes of the ASCR Morphology and kinematics of narrow-line regions in Seyfert galaxies

Stoklasová, Ivana; Jungwiert, Bruno; Ferruit, P.
Astronomický ústav, 2004

Variability of accreting sources at very high time resolution
Bursa, Michal
2004 - English We are carrying out a project to study rapid variability of radiation originating from accreting compact objects. Our goal is to examine fluctuations of the radiation flux occuring on the light-crossing time scales, taking into account effects of strong gravitational field. Řešíme projekt podrobného studia rychlé časové proměnnosti záření vznikajícího v blízkosti akreujících kompaktních objektů. Cílem je prozkoumání fluktuací zářivého toku na časových škálách srovnatelných s dobou průletu světla. Bereme v úvahu efekty silné gravitace. Keywords: black holes; accretion; relativity Available at various institutes of the ASCR Variability of accreting sources at very high time resolution

We are carrying out a project to study rapid variability of radiation originating from accreting compact objects. Our goal is to examine fluctuations of the radiation flux occuring on the ...

Bursa, Michal
Astronomický ústav, 2004

Decaying orbits near a rotating black hole
Pecháček, T.; Karas, Vladimír
2004 - English We consider orbits of a test body near a rotating black hole. The orbits are perturbed by two effects which drive them away from purely geodesic motion. V této práci zkoumáme dráhy testovacích částic v blízkosti rotující černé díry.. Dráhy jsou ovlivněny perturbacemi, které způsobují jejich pomalý vývoj. Keywords: black holes; accretion; relativity Available at various institutes of the ASCR Decaying orbits near a rotating black hole

We consider orbits of a test body near a rotating black hole. The orbits are perturbed by two effects which drive them away from purely geodesic motion....

Pecháček, T.; Karas, Vladimír
Astronomický ústav, 2004

General aspects of nonlinear resonance 3:2 in QPO context
Horák, Jiří
2004 - English In the resonant model, quasi periodic oscillations (QPOs) are supposed to be consequence of a nonlinear resonance between modes of oscillations within innermost parts of an accretion disk. Zkoumáme rezonanční model kvaziperiodických oscilací (QPO), podle něhož tento efekt souvisí s módy akrečního disku. Keywords: black holes; accretion; relativity Available at various institutes of the ASCR General aspects of nonlinear resonance 3:2 in QPO context

In the resonant model, quasi periodic oscillations (QPOs) are supposed to be consequence of a nonlinear resonance between modes of oscillations within innermost parts of an accretion ...

Horák, Jiří
Astronomický ústav, 2004