A5040957887- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Gyrotron and Vacuum Electronics Research
- Galaxies: Formation, Evolution, Phenomena
- Plant and Fungal Interactions Research
- Computational Fluid Dynamics and Aerodynamics
- Magnetic confinement fusion research
- Particle Accelerators and Free-Electron Lasers
- Plant Disease Management Techniques
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Terahertz technology and applications
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Plant Pathogens and Fungal Diseases
University of the Free State
1993-2024
ABSTRACT At optical/ultraviolet energies, blazars display an underlying thermal (unpolarized) contribution from the accretion disc, torus, and line-emitting regions, diluting polarized emission jet-component. Optical polarimetry can be used to disentangle non-thermal components, place constraints on particle populations acceleration mechanisms responsible for emission. We present results of a linear optical spectropolarimetric observing campaign 18 (six BL Lac-type objects 12 flat-spectrum...
During country‐wide surveys of Eucalyptus plantations for Cryphonectria canker, cankers distinctly different from those usually associated with cubensis were observed. These less severe and exemplified by cracked slightly swollen areas on the bark. Endothia gyrosa , a well‐known pathogen woody plants including spp., was consistently these cankers. The is easily distinguished C. presence orange‐brown stromata non‐septate ascospores. Inoculations grandis resulted in lesions similar to observed...
In this paper three dimensional relativistic hydrodynamic simulations of AGN jets are presented to investigate the FR I/FR II dichotomy. Three which illustrates difference in morphology for high/low Lorentz factor injection as well a stratified background medium. factors 10 and 1.0014 were used high low cases respectively. The show division based on their initial luminosity. An additional simulation was set up evolution jet if mass lowered after certain time. A synchrotron emission model...
At optical/ultraviolet energies, blazars display an underlying thermal (unpolarized) contribution from the accretion disc, torus and line emitting regions, diluting polarized emission jet-component. Optical polarimetry can be used to disentangle non-thermal components, place constraints on particle populations acceleration mechanisms responsible for emission. We present results of a linear optical spectropolarimetric observing campaign 18 (6 BLLs 12 FSRQs) undertaken with Southern African...
The discovery of the white dwarf binary system AR Scorpii (AR Sco) with its fascinating non-thermal dominated multi-frequency emission has sparked renewed interest in potential high energy gamma-ray from pulsars. Spectral Energy Distribution (SED) below and above optical shows evidence synchrotron emission, pulsed X-ray bands at spin period ($P_{*} = 117 \, \mbox{s}$) as well a beat ($P_{\rm b} 118.1 period. From an perspective, highly magnetic rotating can accelerate particles to TeV...
The discovery of the white dwarf binary system AR Scorpii (AR Sco) with its fascinating non-thermal dominated multi-frequency emission has sparked renewed interest in potential high energy gamma-ray from pulsars. Spectral Energy Distribution (SED) below and above optical shows evidence synchrotron emission, pulsed X-ray bands at spin period (P ∗ = 117 s) as well a beat b 118.1 period. From an perspective, highly magnetic rotating can accelerate particles to TeV energies. In this study,...
No abstract available.
Grid based numerical hydrodynamic codes have been used to simulate the evolution of a variety astrophysical environments, ranging from stellar winds accretion disks in binary systems. These simulations can be as valuable tools correlate theoretical models and observational data. In this study grid relativistic simulation is created, using freely available code PLUTO ver 4.2, possible causes variability AGN. The uses shock-capturing Godunov-type methods solve fluid dynamic conservation...
Abstract Radio-loud Active Galactic Nuclei (AGN) produce relativistic jets that can be modelled with hydrodynamic (RHD) simulations. In this study we present two such simulations of jets, used to investigate the parameters required reproduce structures consistent both FR I and FRII jets. first simulation a Lorentz factor 10 supersonic flow Mach 30 were chosen, while for second 1.0014 4 was used. Over similar distances scales case shows well collimated beam strong shock at interface between...