Number of found documents: 215
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Flows along arch filaments observed in the GRIS `very fast spectroscopic mode'
Gonzalez Manrique, S. J.; Denker, C.; Kuckein, C.; Pastor Yabar, A.; Collados Vera, M.; Verma, M.; Balthasar, H.; Diercke, A.; Fischer, C.E.; Gömöry, P.; Bello González, N.; Schlichenmaier, R.; Cubas Armas, M.; Berkefeld, T.; Feller, A.; Hoch, S.; Hofmann, A.; Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Schmidt, D.; Schmid, W.; Sigwarth, M.; Sobotka, Michal; Solanki, S.K.; Soltau, D.; Staude, J.; Strassmeier, K.G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.A.
2017 - English
A new generation of solar instruments provides improved spectral, spatial, and temporal resolution, thus facilitating a better understanding of dynamic processes on the Sun. High-resolution observations often reveal multiple-component spectral line profiles, which provides information about the chromospheric velocity and magnetic fine structure. We observed an emerging flux region, including two small pores and an arch filament system, on 2015 April 17 with the "very fast spectroscopic mode" of the GREGOR Infrared Spectrograph (GRIS) situated at the 1.5-meter GREGOR solar telescope at Observatorio del Teide, Tenerife, Spain. We discuss this method of obtaining fast (one per minute) spectral scans of the solar surface and its potential to follow dynamic processes on the Sun. We demonstrate the performance of the "very fast spectroscopic mode" by tracking chromospheric high-velocity features in the arch filament system. Keywords: Sun; chromosphere; photosphere Available at various institutes of the ASCR
Flows along arch filaments observed in the GRIS `very fast spectroscopic mode'

A new generation of solar instruments provides improved spectral, spatial, and temporal resolution, thus facilitating a better understanding of dynamic processes on the Sun. High-resolution ...

Gonzalez Manrique, S. J.; Denker, C.; Kuckein, C.; Pastor Yabar, A.; Collados Vera, M.; Verma, M.; Balthasar, H.; Diercke, A.; Fischer, C.E.; Gömöry, P.; Bello González, N.; Schlichenmaier, R.; Cubas Armas, M.; Berkefeld, T.; Feller, A.; Hoch, S.; Hofmann, A.; Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Schmidt, D.; Schmid, W.; Sigwarth, M.; Sobotka, Michal; Solanki, S.K.; Soltau, D.; Staude, J.; Strassmeier, K.G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.A.
Astronomický ústav, 2017

Cristannus de Prachaticz’s Treatises on the Astrolabe
Hadrava, Petr; Hadravová, Alena
2017 - English
The authors' computer methods of collation and statistical treatment of variant readings are summarized and illustrated on the example of the critical edition of the treatises on Composition and Use of the Astrolabe written by the 15th-century Czech scholar Cristannus de Prachaticz.\n Keywords: history of astronomy; computer-asisted critical editions; digital stematology Available at various institutes of the ASCR
Cristannus de Prachaticz’s Treatises on the Astrolabe

The authors' computer methods of collation and statistical treatment of variant readings are summarized and illustrated on the example of the critical edition of the treatises on Composition and Use ...

Hadrava, Petr; Hadravová, Alena
Astronomický ústav, 2017

Study of Cataclysmic Variables with the Satellites LOFT and Gaia
Hudec, René; Šimon, Vojtěch
2015 - English
The goal of this paper is to discuss the capabilities of ESA satellite missions Gaia (already in space) and LOFT\n(considered for the ESA M4 slot) for investigation of cataclysmic variables (CVs). Both Gaia and LOFT\ncan contribute to study of CVs and related objects. Spectrophotometry and low dispersion spectroscopy are the most important for CV analyses with the observations of Gaia. We present the possible strategies for investigation of CVs in the sampled photometric\nand spectroscopic data provided by Gaia. E.g. statistical properties of the long-term activity of various types of CVs can be determined from them. LOFTcan be a promising satellite to provide a sensitive X-ray monitor which will enable to investigate the little studied long-term activity of various types of CVs (especially the magnetic ones) in the X-ray band. Keywords: catalysmic variables; dwarf novae -; intermediate polar Available at various institutes of the ASCR
Study of Cataclysmic Variables with the Satellites LOFT and Gaia

The goal of this paper is to discuss the capabilities of ESA satellite missions Gaia (already in space) and LOFT\n(considered for the ESA M4 slot) for investigation of cataclysmic variables (CVs). ...

Hudec, René; Šimon, Vojtěch
Astronomický ústav, 2015

Activity of the Polar AM Her (RX J1816.2+4952): A Short Review
Šimon, Vojtěch; Henden, A.
2015 - English
We show that AM Her displays the transitions between the high and low states with an intermittently existing dominant\ncycle with length between 400 and 800 days. Moreover, these transitions accumulate in clusters, which produces an\nadditional long cycle after smoothing; a single isolated short episode of the low state does not suggest a break of this cycle. The seasons of existence of the cycle can be controlled by the lifetime of the active regions (e.g. prominences, spots) on the donor. In some high-state episodes, a higher luminosity of the bremsstrahlung emission is not accompanied by a higher optical (cyclotron+stream) emission. Part of the bremsstrahlung emission can be buried in some episodes. Changes of\nthe structure of the accretion region(s) are necessary to explain the variations of the optical and X-ray activity in the\nhigh-state episodes of AM Her. Keywords: catalysmic variables; polars; emission mechanism Available at various institutes of the ASCR
Activity of the Polar AM Her (RX J1816.2+4952): A Short Review

We show that AM Her displays the transitions between the high and low states with an intermittently existing dominant\ncycle with length between 400 and 800 days. Moreover, these transitions ...

Šimon, Vojtěch; Henden, A.
Astronomický ústav, 2015

GLORIA and Study of Cataclysmic Variables
Šimon, Vojtěch; Hudec, René
2015 - English
We report here on the ongoing EU FP7 Project GLORIA (GLObal Robotic-telescopes Intelligent Array) with emphasis on possibility of investigation of cataclysmic variables by users. GLORIA will enable the rst free and open-access network of robotic telescopes in the world. We show several examples of the not often used topics (but suitable for GLORIA) for the studies of activity of cataclysmic variables, e.g. search for outbursts in intermediate polars and the uctuations of/nbrightness in their quiescence, and investigation of the optical counterparts of supersoft X-ray sources. Keywords: catalysmic variables; spectroscopy; low-dispersion spectra Available at various institutes of the ASCR
GLORIA and Study of Cataclysmic Variables

We report here on the ongoing EU FP7 Project GLORIA (GLObal Robotic-telescopes Intelligent Array) with emphasis on possibility of investigation of cataclysmic variables by users. GLORIA will enable ...

Šimon, Vojtěch; Hudec, René
Astronomický ústav, 2015

Equilibria of charged dust tori in a dipole magnetic field: hydrodynamic approach
Slaný, P.; Kovář, J.; Stuchlík, Z.; Karas, Vladimír
2014 - English
The authors present Newtonian model of non-conductive charge perfect fluid tori orbiting in combined spherical gravitational and dipolar magnetic fields, focusing on stationary, axisymmetric toroidal structures. Keywords: dust tori; electric charge; magnetic field Available at various institutes of the ASCR
Equilibria of charged dust tori in a dipole magnetic field: hydrodynamic approach

The authors present Newtonian model of non-conductive charge perfect fluid tori orbiting in combined spherical gravitational and dipolar magnetic fields, focusing on stationary, axisymmetric toroidal ...

Slaný, P.; Kovář, J.; Stuchlík, Z.; Karas, Vladimír
Astronomický ústav, 2014

Polarization vector transport in Kerr geometry
Bursa, Michal; Horák, Jiří; Karssen, G.
2014 - English
In this paper the authors proved a set of practical formulae that are helpful in calculating the orientation of polarization vectors that are parallel transported from a region of strong gravitational field of a Kerr black hole to a distant observer. Keywords: polarization; black hole; electromagnetic radiation Available at various institutes of the ASCR
Polarization vector transport in Kerr geometry

In this paper the authors proved a set of practical formulae that are helpful in calculating the orientation of polarization vectors that are parallel transported from a region of strong gravitational ...

Bursa, Michal; Horák, Jiří; Karssen, G.
Astronomický ústav, 2014

An Introduction to relativistic magnetohydrodynamics. II. Case of stationary electro-vacuum fields around black holes
Karas, Vladimír
2014 - English
The lecture on electrodynamical effects near black holes. The author summarize the basic equations of relativistic electrodynamics in terms of spin-coefficien formalism. Keywords: black holes; electromagnetic fields; relativity Available at various institutes of the ASCR
An Introduction to relativistic magnetohydrodynamics. II. Case of stationary electro-vacuum fields around black holes

The lecture on electrodynamical effects near black holes. The author summarize the basic equations of relativistic electrodynamics in terms of spin-coefficien formalism.

Karas, Vladimír
Astronomický ústav, 2014

Simulating Compton scattering using Monte Carlo method: COSMOC library
Adámek, K.; Bursa, Michal
2014 - English
The authors present properties and functionality of the COSMOC library designed to exploit basic features of Compton scattering process and its computational modelling. Keywords: Monte Carlo; Compton scattering; C++ Available at various institutes of the ASCR
Simulating Compton scattering using Monte Carlo method: COSMOC library

The authors present properties and functionality of the COSMOC library designed to exploit basic features of Compton scattering process and its computational modelling.

Adámek, K.; Bursa, Michal
Astronomický ústav, 2014

Tidal disruption events from a nuclear star cluster as possible origin of transient relativistic spectral lines near SMBH
Karas, Vladimír; Dovčiak, Michal; Kunneriath, Devaky; Yu, W.; Zhang, W.
2014 - English
The authors discuss a possibility that a tidal disruption event near a dormant supermassive black hole can give rise to spectral features of iron in 6-7keV X-ray signal. Keywords: accretion discs; black hole physics Available at various institutes of the ASCR
Tidal disruption events from a nuclear star cluster as possible origin of transient relativistic spectral lines near SMBH

The authors discuss a possibility that a tidal disruption event near a dormant supermassive black hole can give rise to spectral features of iron in 6-7keV X-ray signal.

Karas, Vladimír; Dovčiak, Michal; Kunneriath, Devaky; Yu, W.; Zhang, W.
Astronomický ústav, 2014

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