Conveners
Astrophysics & Space Science: Transients
- Soebur Razzaque (University of Johannesburg)
Astrophysics & Space Science: Gamma-ray bursts
- Geoff Beck (University of Witwatersrand)
Astrophysics & Space Science: Near Earth Environment
- KATLEGO MOLOTO (NORTH WEST UNIVERSITY)
Astrophysics & Space Science: Cosmology
- Getachew Mekonnen Mengistie (University of Zululand)
Astrophysics & Space Science: Miscellaneous
- Geoff Beck (University of Witwatersrand)
Astrophysics & Space Science: Solar Observations
- Lerato Shikwambana (SANSA)
Astrophysics & Space Science
- KATLEGO MOLOTO (NORTH WEST UNIVERSITY)
- Geoff Beck (University of Witwatersrand)
Astrophysics & Space Science: Binaries
- Geoff Beck (University of Witwatersrand)
Astrophysics & Space Science: Cosmology II
- Shambel Sahlu (North-West University)
Astrophysics & Space Science: Cosmic Ray Modelling
- Geoff Beck (University of Witwatersrand)
Astrophysics & Space Science: Miscellaneous II
- KATLEGO MOLOTO (NORTH WEST UNIVERSITY)
Astrophysics & Space Science
- There are no conveners in this block
MeerTRAP is a European Research Council funded search for fast radio transients with MeerKAT. The project uses a custom backend at the telescope that operates commensally with the MeerKAT Large Survey Projects (LSPs), collecting voltages from the antennas to form hundreds of beams on sky. These beams are continuously searched for millisecond-duration pulses from fast radio transients such as...
Pulsars, the aftermath of core-collapse supernovae, rotate rapidly and have immense magnetic fields. These characteristics lead to broad-band radio emission. The radio pulses are believed to be emitted above the pulsar’s magnetic polar caps. The MeerKAT radio telescope, which is situated in Carnarvon in the Northern Cape, South Africa, is ideally suited to discover new pulsars due to it being...
Gamma-Ray Burst (GRB) 221009A was once in a century event detected from radio to very high-energy (VHE) gamma rays. It was the first time that $> 10$ TeV gamma rays were detected from a GRB. Even though GRB 221009A was a relatively nearby event at redshift 0.15, detection of a 18 TeV photon by the LHAASO detector and of a 251 TeV photon by the Carpet-2 detector challenge conventional radiation...
Short gamma-ray bursts (SGRBs) are energetic impulses with emissions that last for less than 2 s and have a hard spectra. They are cosmological entities and they originate from compact binary mergers like binary systems. Moreover, there is evidence that they are also tied to gravitational wave events after the detection of GRB170817A. However, these properties are not unique to them. There are...
Since the first detection of gamma-ray bursts (GRBs) in 1967, GRBs have been an active
subject of study with many questions still left unanswered. Though the physics of GRB afterglows
is relatively simple and more well known, there is still much discussion regarding that of the
prompt emission phase of GRBs. Several models, including synchrotron models with both ordered
and random magnetic...
Wildfires are among the major and prevalent environmental disturbance agents of our time and affect human health, the infrastructure and the earth-atmosphere mechanisms. Wildfires can be ignited naturally by lightning or humans, either accidentally or to accomplish management objectives such as clearing and reduction in fuel loads. Wildfires are unique in themselves as they are driven by...
Major space weather events may contribute to ionospheric delay where additional noise is introduced into observations of the satellite signal. As a result, the accuracy and reliability of the Global Positioning System (GPS) is compromised. This study aims to conduct an analysis of the ionospheric storm effects using Total Electron Content (TEC) derived from ionosonde and GPS observations...
This research study investigates the behavior of equatorial ionization anomaly (EIA) during geomagnetic storms over the African sector (40° S – 50° N and 20° E - 40° E) using a global navigation satellite systems (GNSS) derived total electron content (TEC) within the period of 2008 to 2013. To identify the geomagnetic storms, the criteria of the disturbance storm time, Dst ≤ -30 nT, and the...
Semidiurnal and diurnal tides are known to have a significant impact upon the momentum balance in the mesosphere-lower thermosphere (MLT) region, and on the distribution of atmospheric constituents. In general, tidal structures in the middle atmosphere are exceptionally complex, and thus their successful modelling
requires consideration of a wide range of atmospheric phenomena, such as...
The cosmological perturbations for a multi-component cosmic medium is investigated
in the frame-work of the modified teleparallel gravity. The evolution equations of theperturbations for each component fluid are derived following the covariant and gaugeinvariant perturbations formalism. For the analysis of our results, we consider the power-law $f(T)$ gravity toy model and study the growth of...
Decades of astronomical observation have shown that the universe is expanding at an accelerated rate. The standard model of cosmology is the closest we have to a standard theory of gravitation but it fails to adequately describe our universe without the ad hoc introduction of dark energy and dark matter to late-time cosmology and inflation to early-universe cosmology. This has certainly...
The dwarf spheroidal galaxies orbiting the Milky Way galaxy, particularly the Dark Matter-dominated Ultrafaints, possess excellent discovery potential as observational targets for DM indirect detection. We assess hypothetical, leptophilic WIMPs in the 1 TeV–2 TeV range, with four dwarf galaxies chosen as potential observational targets. These are the Classical dwarf galaxies Sculptor and...
The advent of the MeerKAT, a precursor to the Square Kilometre Array (SKA), has driven the need to invest in human capacity development in radio astronomy. The North-West University (NWU) is in the process of commissioning a small four-element radio interferometer. Nooitgedacht Observatory, owned by the NWU, was selected to house the radio telescopes due to the low level of noise present at...
In this work we derive the distance modulus from Gaia parallaxes for Kepler Input Catalogue (KIC) stars located within 10 arcmin in the field of NGC 6819. The mean distance modulus is used to determine probable new KIC members of NGC 6819 cluster. We find 7 probable KIC new astrometric distance members which have been previously overlooked in the literature as revealed by Gaia Data Release 2...
The purpose of the experiment was to determine the effect the sunspot number would have on the number of solar flares. The hypothesis stated that as the sunspot number increased, the number of solar flares would also increase during the same time period. With the ability to predict the occurrence of solar flares from sunspot activity, it may be possible to prevent the damage to power grids and...
The Centre for Space Research (CSR) at the North-West University (NWU), South Africa, commissioned a solar telescope in 2021. The weather in Potchefstroom, South Africa, is ideal for solar observations for the biggest part of the year, especially during the dry winter months. The first science application of the solar telescope was investigating the differential rotation rate of the Sun. The...
The main aim of this study is to perform statistical analysis of ground level enhancement (GLE) and forbush decrease (FD) associated with solar events, such as coronal mass ejections (CMEs), solar energetic particles (SEPs) and solar flares. The study will also investigate which of the solar events has the greatest influence in terms of GLEs and FD magnitudes. The period of study covers the...
Understanding the complex relationship between nuclear activity, star formation, and galaxy growth is crucial for disentangling the mechanisms driving galaxy evolution. This project investigates how nuclear activity regulates star formation and galaxy growth at higher redshifts (z > 1). We specifically explore the correlations between black hole accretion rate (BHAR), star formation rate...
Using Ultra-Luminous X-ray (ULX) sources as progenitors of compact binary systems, we estimate the coalescence rate of compact binary systems. ULXs are extra-galactic X-ray sources with apparent luminosity > 10^{39} erg/s. They are thought to be accreting NS or BH. The mechanism of how these systems reach such high luminosity is still unknown. 10^{39} erg/s is above the Edington accretion...
In this work we derive limits on the WIMP-nucleon scattering cross-section by comparing the potential heat flow within the Earth from Dark Matter capture and subsequent annihilation to the observational value. This effect has been argued previously in the literature to provide a potential link to mass extinction phenomena on Earth. However, we focus on whether additional heat-flux from dark...
The nature of dark matter remains a major unresolved mystery in modern cosmology. In this work we explore the use of the MeerKAT Galaxy Cluster Legacy Survey in placing limits on the allowed annihilation cross-section for a variety of possible WIMP models. In so doing we demonstrate that MeerKAT is competitive with best available results in the literature, excluding WIMPs annihilating into...
The study of galactic cosmic ray (GCR) antiparticles can potentially lead to new insights into fundamental physics, in particular in the search for indirect evidence of dark matter annihilation. Identifying the signature(s) of such processes, however, is complicated by the heliospheric modulation of these particles. Modulation becomes less significant at higher energies, and therefore it would...
Drift effects due to gradients and curvature in the heliospheric magnetic field (HMF) have long been known to affect cosmic ray (CR) modulation. Thus far, only drift effects due to the geometry of the HMF proposed by Parker (1958) have been studied. However, several other HMF models exist, including the model proposed by Fisk (1996), which, notably, has a latitudinal component. The Fisk-Parker...
Understanding the mechanisms behind Solar Energetic Particle (SEP) transport in the inner heliosphere aids in the effort to develop accurate and predictive space weather models.
Modelling several sets of observations over different events by the Solar Orbiter, WIND, GOES, and SOHO spacecraft, at a distance between 0.3 - 1.0 AU, provides transport parameters that cannot be measured or...
Observing and modelling solar energetic particles (SEPs) aids to establish an early warning system to prevent any hazardous impact on humans and technology in space. Using the electron intensity observations from the MAVEN and WIND spacecraft, one-dimensional SEP transport is simulated during MAVEN’s voyage along the Parker-Hohmann orbit from Earth to Mars. The soft X-ray data from GOES was...
Commensal searching for radio transients/variables in MHONGOOSE Large Survey Project (LSP).
The MeerKAT radio telescope is the newly built South African precursor radio telescope array for the mid frequency component of the Square Kilometre Array (SKA1-Mid). Its excellent sensitivity and wide field of view, combined with commensal access to a large number of MeerKAT surveys, allows...
Astrospheres are bullet-shaped structures formed by the motion of stars through the interstellar medium. This study analyse the impact of the star's outflow parameters, including density, temperature, and magnetic field, on the evolution of the astrosphere using hydrodynamic and magnetohydrodynamical models. The analysis focuses on the compression ratio, velocity and width of the bow shock...
A detailed theoretical investigation is conducted using the Sagdeev pseudopotential formalism to investigate the effects of ion beams on ion-acoustic modes in plasma models with two species of adiabatic ions and one or two (cool and hot) species of electrons which are Boltzmann distributed. One or both ion species are considered to be drifting (beam) components. The linear analysis shows that...
