Search Publications
Space debris observations with the Slovak AGO70 telescope: Astrometry and light curves
Šilha, Jiří; Krajčovič, Stanislav; Zigo, Matej +12 more
The Faculty of Mathematics, Physics and Informatics of Comenius University in Bratislava, Slovakia (FMPI) operates its own 0.7-m Newtonian telescope (AGO70) dedicated to the space surveillance tracking and research, with an emphasis on space debris. The observation planning focuses on objects on geosynchronous (GEO), eccentric (GTO and Molniya) an…
Cut-off features in interplanetary solar radio type IV emission
Pohjolainen, Silja; Talebpour Sheshvan, Nasrin
Solar radio type IV bursts can sometimes show directivity, so that no burst is observed when the source region in located far from the solar disk center. This has recently been verified also from space observations, at decameter wavelengths, using a 3D-view to the Sun with STEREO and Wind satellites. It is unclear whether the directivity is caused…
Analysis of a long-duration AR throughout five solar rotations: Magnetic properties and ejective events
Ugarte-Urra, Ignacio; Mandrini, Cristina H.; Cremades, Hebe +4 more
Coronal mass ejections (CMEs), which are among the most magnificent solar eruptions, are a major driver of space weather and can thus affect diverse human technologies. Different processes have been proposed to explain the initiation and release of CMEs from solar active regions (ARs), without reaching consensus on which is the predominant scenari…
Wavelet analysis of low frequency plasma oscillations in the magnetosheath of Mars
Fränz, M.; Bolzan, M. J. A.; Echer, E. +1 more
Wavelet analysis was employed to identify the major frequencies present in the plasma oscillations in the Martian magnetosheath. We have selected magnetosheath crossings and applied the Morlet wavelet transform to the electron density and temperature data, obtained from the Analyzer of Space Plasmas and Energetic Atoms experiment (ASPERA-3), onboa…
The complications of learning from Super Soft Source X-ray spectra
Ness, Jan-Uwe
Super Soft X-ray Sources (SSS) are powered by nuclear burning on the surface of an accreting white dwarf, they are seen around 0.1-1 keV (thus in the soft X-ray regime), depending on effective temperature and the amount of intervening interstellar neutral hydrogen (NH). The most realistic model to derive physical parameters from observe…
On extreme space weather events: Solar eruptions, energetic protons and geomagnetic storms
Miteva, Rositsa
The purpose of this study is to identify the extreme space weather events in the available satellite and ground-based databases and to relate them to other associated or accompanied solar activity events. Solar flares, coronal mass ejections, energetic protons and geomagnetic storms are selected among all manifestations/consequences of solar activ…
Statistical analysis of solar wind parameter variation with heliospheric distance: Ulysses observations in the ecliptic plane
Bolzan, M. J. A.; Echer, E.; Franco, A. M. S.
The interplanetary magnetic field magnitude Bo, proton density Np and solar wind speed Vsw data from Ulysses spacecraft during its interplanetary cruise interval from Earth to Jupiter, from 18 November 1990 to 31 January 1992, are analyzed in this study. Statistical and wavelet techniques are employed to characteri…
Gaia: The Galaxy in six (and more) dimensions
Pancino, Elena
The ESA cornerstone mission Gaia was successfully launched in 2013, and is now scanning the sky to accurately measure the positions and motions of about two billion point-like sources of 3 ≲ V ≲ 20.5 mag, with the main goal of reconstructing the 6D phase space structure of the Milky Way. The typical uncertainties in the astrometry will be in the r…
Using cross correlation to estimate Doppler frequency
Li, Fei; Yan, Jianguo; He, Qingbao +2 more
Doppler frequency estimation with high accuracy is very important for precise orbit determination and scientific studies in deep space exploration. In this paper, we propose a new method which implements cross correlation of only received signals from one single station to estimate Doppler frequency. The algorithm is relatively simple and it can a…
X-ray properties of dwarf nova EY Cyg and the companion star using an XMM-Newton observation
Balman, Şölen; Nabizadeh, Armin
We present the X-ray analysis of dwarf nova EY Cyg using the 45 ks XMM-Newton observatory archival data obtained in quiescence. We find orbital modulations in X-rays. We simultaneously fitted EPIC pn, MOS1 and MOS2 data using a model for interstellar medium absorption (tbabs) and a multi-temperature plasma emission model with a power-law distribut…