Conveners
Astrophysics
- John Menzies (South African Astronomical Observatory)
Astrophysics
- Patrick Woudt (Department of Astronomy, University of Cape Town)
Astrophysics
- Thulani Jili (University of Zululand)
Astrophysics
- John Menzies (South African Astronomical Observatory)
Astrophysics
- Geoff Beck (University of Witwatersrand)
Astrophysics
- Geoff Beck (University of Witwatersrand)
Astrophysics
- Brian van Soelen (University of the Free State)
- Zama Thobeka Katamzi-Joseph (South African National Space Agency)
Astrophysics
- Zama Thobeka Katamzi-Joseph (South African National Space Agency)
- Brian van Soelen (University of the Free State)
Ms
Miriam Mumbua Nyamai
(University of Cape Town)
09/07/2019, 10:00
Track D1 - Astrophysics
Oral Presentation
A nova eruption occurs on the surface of a white dwarf following extensive accretion of material from a less evolved companion star. Their study provides an opportunity to understand the emission processes of expelled material and high-energy emitting shocks among others. Modelling radio observations as an expanding gas emitting free-free emission give insights to ejected mass, the velocity of...
Ms
Andri Prozesky
(Unisa)
09/07/2019, 10:20
Track D1 - Astrophysics
Oral Presentation
Astronomical masers occur when radiation is amplified by the process of stimulated emission over long path lengths, producing line emission that is much brighter than spectral lines produced by spontaneous transitions. Molecular astronomical masers have proven to be a useful tool to probe conditions in a wide variety of astronomical sources. Masers are also produced by atomic hydrogen formed...
Prof.
Patrick Woudt
(Department of Astronomy, University of Cape Town)
09/07/2019, 10:40
Track D1 - Astrophysics
Oral Presentation
In July 2018, MeerKAT was inaugurated and started its science mission. One of the 5-year legacy programs on MeerKAT is the ThunderKAT large survey project which aims to find, identify and understand high energy astrophysical processes via their radio emission. This is achieved through a program of surveying and monitoring Galactic synchrotron transients (X-ray binaries, Cataclysmic variables,...
Dr
John Menzies
(South African Astronomical Observatory)
09/07/2019, 11:20
Track D1 - Astrophysics
Oral Presentation
Infrared observations of newly-discovered Mira variables in Local Group galaxies have shown that they follow a tight period-luminosity relation that can be used to determine a distance to any nearby galaxy found to harbour such stars. This
presentation will show the outcome of a campaign with the IRSF telescope at Sutherland and consider the implications of the result for the distance scale...
Ms
Rozeena Ebrahim
(School of Physics, University of the Witwatersrand, Johannesburg)
09/07/2019, 11:40
Track D1 - Astrophysics
Oral Presentation
The Circinus galaxy is a composite starburst/Seyfert galaxy which features 3 kpc scale radio lobe outflows along its minor axis. It is located 4 Mpc away, which makes it a unique target to study the physical nature of these outflows. Our task will be to investigate whether they originate from star formation or jets that resulted from an active galactic core. The MeerKAT array can perform 20...
Ms
Narges Hatamkhani
(University of Cape town)
09/07/2019, 12:00
Track D1 - Astrophysics
Oral Presentation
The aim in this survey is to map the distribution of galaxies in the potential clusters that lie within the newly discovered Vela Supercluster (VSCL) found by Kraan-Korteweg et al. (2017). This supercluster at a redshift of about 18000 km/s appears as extended and massive as the Shapley Supercluster. The VSCL is partly hidden in the Zone of Avoidance (ZoA) and so the Near Infrared (NIR) is the...
Ms
Sumari Hattingh
(North-West University)
09/07/2019, 12:20
Track D1 - Astrophysics
Oral Presentation
Galaxy groups offer an excellent opportunity to study the impact of galaxies on their intergalactic medium (IGM), and vice versa, as the galaxy's heating process effects are more visible due to the groups' lower density and mass compared to clusters of galaxies. This project is part of an optical observational campaign to observe the Complete Local-Volume Groups Sample (CLoGS), which is a...
Mr
Charles takalana
(University of the Witwatersrand)
09/07/2019, 12:40
Track D1 - Astrophysics
Oral Presentation
Probing the Dark ages (DA) and the Epoch of reionization (EoR), remains one of the challenges facing modern cosmology. Numerous probes have been proposed for exploration of these epochs and efforts are already under-way to detect signatures from them through observations of the 21cm cosmological signal, which corresponds to the 21cm transition of atomic hydrogen. Recently the EDGES...
Dr
Thulani Jili
(University of Zululand)
10/07/2019, 10:00
Track D1 - Astrophysics
Oral Presentation
More than two decades after the birth of South Africa's democracy we find ourselves in an exciting era for astronomy in South Africa. The MeerKAT and SALT telescopes are producing world class science, the number of astronomers in the country are steadily growing, government funding is significant, and hundreds of students are finding opportunities within the broad scientific and technical...
Ms
Isabella Rammala
(Rhodes university)
10/07/2019, 10:20
Track D1 - Astrophysics
Oral Presentation
Profiles from radio pulsars typically show a strong dependence on observing frequency. This depends both on the intrinsic radio emission mechanism, as well as the interaction of the radio waves with the interstellar medium (ISM) that lies between the pulsars and our detectors on Earth, due mostly to the effects of dispersion and scattering. The aim of our project is to study how to best...
Mr
Louis Du Plessis
(NWU, Potchefstroom, Department of Physics)
10/07/2019, 10:40
Track D1 - Astrophysics
Oral Presentation
Marsh et al. (2016) detected radio and optical pulsations from the binary system AR Scorpii (AR Sco). This system, with an orbital period of 3.55h, is composed of a cool, low-mass star and a white dwarf with a spin period of 1.95min. X-ray pulsations have also been detected from this source (Takata et al. 2018). Optical observations by Buckley et al. (2017) showed that the polarimetric...
Mr
Christian van der Merwe
(North-West University, Centre for Space Research)
10/07/2019, 11:20
Track D1 - Astrophysics
Oral Presentation
Black widow and redback systems are compact binaries in which the pulsar heats and may even ablate its low-mass companion by its intense wind of relativistic particles and emission. The pulsar wind drives mass loss from the companion, and an intra-binary shock forms as a site of particle acceleration. Radio, optical and X-ray follow-up of unidentified Fermi Large Area Telescope (LAT) sources...
Mr
Mfuphi Ntshatsha
(University of Johannesburg)
10/07/2019, 11:40
Track D1 - Astrophysics
Oral Presentation
Some of the brightest, in electromagnetic radiation, objects in the universe are surprisingly not only stars but galaxies. Active galaxies, at their core, have supermassive black holes which accelerate charged particles along an axis. The acceleration of these particles results in various emission processes. The emission is propagated in jets whose cones lie along this axis and is observable...
Mr
Ahmed Ayad Mohamed Ali
(University of the Witwatersrand)
10/07/2019, 12:00
Track D1 - Astrophysics
Oral Presentation
An outstanding result of modern cosmology is that only a small fraction of the total matter content of the universe is made of baryonic matter, while the vast majority is constituted by dark matter (DM). However, the nature of such component is still unknown and might be a matter of long standing controversies. In principle, the nature of DM can be understood through looking for light scalar...
Ms
Ashlynn Le Ray
(University Of The Witwaterand)
10/07/2019, 12:20
Track D1 - Astrophysics
Oral Presentation
The star formation history (SFH) of the Universe is of fundamental importance to cosmology, not only to galactic formation itself but also for ongoing efforts to determine cosmological parameters and matter content of the Universe. Measurements of the extragalactic background light (EBL) as a function of redshift can constrain models of the SFH, including the initial mass function (IMF) and...
Ms
Charissa Button
(University of the Witwatersrand)
10/07/2019, 12:40
Track D1 - Astrophysics
Poster Presentation
Radio relics are non-thermal, steep-spectrum (α < -1) diffuse radio sources found in the peripheral regions of galaxy clusters. The emission is produced through synchrotron radiation as relativistic electrons (γ >> 1000) move in helical paths through the magnetic fields of the intracluster medium (ICM). As the time it would take for the electrons to diffuse over a distance greater than 50 kpc...
Dr
Shyam Das
(P. D. Women's College, Jalpaiguri, India)
11/07/2019, 10:00
Track D1 - Astrophysics
Oral Presentation
In this paper, a physically motivated form of one of the metric potential and a specific choice of the anisotropy has been utilized to obtain closed-form solutions of the Einstein field equation for a spherically symmetric anisotropic matter distribution. This class of solution has been used to develop viable models for observed pulsars. The exterior spacetime is assumed as described by the...
Mr
Pieter Van der Merwe
(North-west University, Center for Space Research)
11/07/2019, 10:20
Track D1 - Astrophysics
Oral Presentation
In 2015 gravitational wave event GW150914 was detected by the advanced Laser Interferometer Gravitational-wave Observatory (aLIGO), with a possible weak transient electromagnetic counterpart GW150914-GBM detected by the Fermi Gamma-ray Burst Monitor (GBM) 0.4s after the detection of the gravitational wave signal. In light of these detections we simulate the dynamics of test particles in the...
Anna-Mia Swart
(North-West University)
11/07/2019, 10:40
Track D1 - Astrophysics
Oral Presentation
One of the most active areas of research in cosmology today involves trying to understand the nature of dark matter and dark energy. In this work we will look at the cosmological background expansion of a universe model filled with a Radiation-Baryon-Chaplygin Gas fluid system. We will show that such a model can solve the dark matter and dark energy problems, at least at the level of the...
Dr
Geoff Beck
(University of Witwatersrand)
11/07/2019, 11:20
Track D1 - Astrophysics
Oral Presentation
The gold-standard of astronomical WIMP hunting has historically been the ability to detect dark matter annihilation signals at thermal relic cross-section required to produce the observed cosmological dark matter abundance. A model's status becomes dubious if expected emissions are not observed at this point, as a weaker cross-section implies this candidate would not supply the bulk of...
Ms
Omphile Rabyang
(Centre for space research, North West University, Potchefstroom Campus)
11/07/2019, 11:40
Track D1 - Astrophysics
Oral Presentation
The recent detection of astrophysical very-high-energy neutrinos by IceCube has spurred an intensive search for their sources. As a possible sources of VHE neutrinos, tidal disruption events (TDEs) have been suggested. Here we investigate a jetted TDE- Swift J1644+57 which is the best measured TDE in multiple wavebands- as a candidate astrophysical neutrino source. TDEs occur when a star...
Mr
Renier Hough
(North-West University)
11/07/2019, 12:00
Track D1 - Astrophysics
Oral Presentation
We are looking at how to constrain ⨍(R)-modified gravity models, such as ⨍(R) =βRn (a toy model) or more realistic ⨍(R)-gravity models like the Starobinsky or Hu-Sawicki model, to cosmological data. We
used 236 intermediate redshift and 123 low redshift Type 1A Supernovae data obtained from the SDSS-II/SNLS3 Joint Light-curve Analysis (JLA), with absolute magnitudes for the B-filter found on...
Ms
Heba Abdulrahman
(North-West University)
11/07/2019, 12:20
Track D1 - Astrophysics
Oral Presentation
Recently a generalized Chaplygin gas has been proposed as a unifying solution to the dark energy and dark matter problems. In this work, we will study the density perturbations of a universe filled with radiation, baryonic matter and the Chaplygin gas fluid and analyse the implications on large-scale structure. We will then compare our model results with power spectrum of the observable universe.
