J. Petrović
A5105527043- Astrophysics and Cosmic Phenomena
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Particle physics theoretical and experimental studies
- Astronomical Observations and Instrumentation
- Particle Detector Development and Performance
- Particle accelerators and beam dynamics
- Pulsars and Gravitational Waves Research
- Scientific Research and Discoveries
- Radio Wave Propagation Studies
- Electromagnetic Compatibility and Measurements
- High-pressure geophysics and materials
- Solar and Space Plasma Dynamics
- Tropical and Extratropical Cyclones Research
- History and Developments in Astronomy
- Magnetic confinement fusion research
- Atmospheric Ozone and Climate
- Photocathodes and Microchannel Plates
Astronomical Observatory
2020-2024
Biotechnical Educational Centre Ljubljana
2022
University of Nis
2019
Croatian Academy of Sciences and Arts
2017
Université Libre de Bruxelles
2008-2014
National Institute for Subatomic Physics
2009-2013
Université Paris-Sud
2013
Université de Toulon
2013
Universidade de Santiago de Compostela
2009-2012
Centre National de la Recherche Scientifique
2010-2012
Since close WR+O binaries are the result of a strong interaction both stars in massive binary systems, they can be used to constrain highly uncertain mass and angular momentum budget during major transfer phase. We explore progenitor evolution three best suited HD 90657, 186943 211853, which characterized by WR/O ratio $\sim$0.5 periods 6..10 days. doing so at different levels approximation: predicting through simple loss estimates, full models with parametrized efficiency, including...
ZZ PsA is a neglected bright southern contact binary system with maximum V magnitude of 9.26. We present the first multi-band photometric analysis and find to be in deep (>95%) an extremely low mass ratio 0.078. The primary has 1.213 M? keeping its reported spectral class F6. In order determine if merger candidate we outline current status regarding instability develop new relationship linking degree contact. that along two other examples from literature candidates while additional three...
The collapsar model for gamma-ray bursts requires three essential ingredients: a massive core, removal of the hydrogen envelope, and enough angular momentum in core. We study current star evolution models solar metallicity to determine which physics is capable producing these ingredients. In particular, we investigate role hydrodynamic magnetic internal transport binary mass transfer. follow rotating single stars systems that include rotational processes both stars. Neglecting fields, show...
Aims.We investigate the influence of metallicity and stellar wind mass loss on radius Wolf-Rayet stars.Methods.We have calculated chemically homogeneous models stars 10 to 200 for two metallicities ( ), without loss, using OPAL opacities. We also constructed theoretical helium main sequences 15, 18, 24 30 with rates a star few intermediate values rate.Results.We confirm extension luminous, metal-rich reported previously by Ishii et al. (1999, PASJ, 51, 417), i.e. inflation hydrostatic...
Photometric observations and analysis of twelve previously poorly studied contact binary systems is presented. All show total eclipses have extremely low mass ratios ranging from 0.072 to 0.15. Also, all characteristics orbital instability with within the theoretical range. Although none demonstrate a significant O'Connell effect at least nine other indicators increased chromospheric magnetic activity.
Cosmic ray air showers produce radio emission, consisting in large part of geosynchrotron emission. Since the radiation mechanism is based on particle acceleration, atmospheric electric field can play an important role. Especially inside thunderclouds fields be present. We examine contribution to emission theoretically and experimentally. Two mechanisms amplification are considered: acceleration shower particles from current that produced by ionization electrons moving field. selected...
We present photometric analysis of three bright red nova progenitor contact binary systems: ASAS J082151-0612.6, TYC 7281-269-1 and 7275-1968-1. The primary components in all systems are solar-type low mass stars with radii somewhat larger than their Zero Age Main Sequence counterparts. secondaries, as most systems, have luminosities well above main sequence All extreme ratios ranging from 0.075 to 0.097 two high degrees contact, excess 75%. separations below the theoretical values for...
ABSTRACT The orbital stability of contact binary systems has been receiving considerable attention recently. Theoretical studies indicate that merger is likely to occur at very low-mass ratios, but the actual mass ratio which may take place be variable and dependent on primary. We consider effects metal content by modelling gyration radius a rotating tidally distorted primary component various values $\rm [Fe/H]$ in range −1.25 +0.5. determine instability for with 0.6 M⊙ ≤ M1 1.4 metallicity...
Aims.The capability of radio antenna arrays to measure cosmic ray air showers with very large zenith angles is explored. This important, since a possible neutrino detection has fulfill two requirements. First: antennas should be able detect inclined showers, and second: it estimate the distance shower maximum, neutrinos are most likely travel far through Earth's atmosphere without interaction induce close ground.
Time-Integrated Searches for Point-like Sources of Neutrinos with the 40-String IceCube Detector Abbasi, R, etal 9 Dec 2010 This work was supported by Director, Office Science, Basic Energy Sciences, U.S. Department under Contract No. DE-AC02-05CH11231. DISCLAIMER document prepared as an account sponsored United States Government. While this is believed to contain correct information, neither Government nor any agency thereof, The Regents University California, their employees, makes...
We discuss the first available binary evolution models which include up-to-date rotational physics for both components, as well angular momentum accretion and spin-orbit coupling. These allow a self-consistent computation of mass transfer efficiency during Roche-lobe overflow phases, determination transition from quasi-conservative to non-conservative evolution. Applications massive systems lead predictions spin rates compact objects in binaries, occurrence gamma-ray bursts collapsars...
Measuring radio pulses from cosmic ray air showers offers various new opportunities. New digital receivers allow measurements of these even in environments that have lots interference. With high bandwidth ADCs and fast data processing it is possible to store the whole waveform information form analyse transient events like after they been recorded. Digital filtering beam forming can be used suppress interference so measure loud environments. LOPES a prototype station for interferometer LOFAR...
We present the results of study close binary UU Cassiopeiae based on previously published multi wavelength photometric and spectroscopic data. Based eclipse timings last 117 years, we find an improved orbital period $\rm P_{o} = 8.519296(8)$ d. In addition, a long cycle length $T$ $\sim$ 270 d in $I_c$-band There is no evidence for change during century, suggesting that rate mass loss from system or exchange between stars should be small. Sporadic rapid brightness drops up to $\Delta$$V$ 0.3...
We discuss which fraction of the matter flowing to companion during a Roche lobe overflow phase can actually be accreted by secondary star. Employing new evolutionary models for massive close binaries include effects rotation both components as well angular momentum accretion and spin-orbit coupling, we propose physical model calculate efficiency in Case A B systems. provide examples showing that cases, high low efficiency, do occur within these models, it seems required observed post-mass...
The LOPES experiment (LOfar Prototype Station) has been built at the KASCADE-Grande in order to test LOFAR (LOw Frequency ARray) technology and demonstrate its capability for radio measurements Extensive Air Showers (EAS). After first positive results framework of we developed next generation antennas, electronics, trigger. main new features are easy calibration antennas with precise detection polarization, good self-triggering. from this design under Karlsruhe. Furthermore background...
The origin of high-energy cosmic rays in the energy range from 1014 to 1018 eV is explored with KASCADE and KASCADE-Grande experiments. Radio signals air showers are measured LOPES experiment. An overview on results given.
Abstract Multi-band ( B , V and R ) photometric spectroscopic observations of six poorly studied contact binaries carried out at the Western Sydney University Las Cumbres Observatory were analyzed using a recent version Wilson–Devenney code. All found to be extreme low mass ratio ranging from 0.073 0.149. are F spectral class with primary component 1.05 M ☉ 1.48 . None show light curve features enhanced choromospheric activity (O’Connel Effect) however five do have significant ultraviolet...
We investigate to what extent the radiation and stellar wind momenta in a massive close binary system can remove part of matter flowing from one towards other star during mass transfer phase. perform radiation-hydrodynamics simulations co-rotating frame made-up two main sequence stars 27 26 4 day orbit. study interaction winds both stars, their photons, with accretion stream originating Roche-lobe filling component. For our simulation, we adopt rate 5 10-6 yr-1, mid-point range values...
LOPES is set up at the location of KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure investigate radio pulses from Extensive Air Showers. Data taken during half a year operation 10 antennas (LOPES-10), triggered by showers observed with have been analyzed. We report about results correlations found measured signals LOPES-10 parameters.