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David Buckley (South African Astronomical Observatory)30/09/2026, 08:30Invited Talk
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Markus Boettcher30/09/2026, 08:40Invited Talk
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Mr Takalani Nemaungani (DSTI)30/09/2026, 08:50Invited Talk
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Dipanjan Mukherjee (IUCAA)30/09/2026, 09:00
Relativistic jets from supermassive blackholes are an important driver of feedback in galaxies with an active black hole. They impact the nearby environment over different physical scales during their lifetime, with varying effects. The jets can act as an important agent of injecting energy in the host's ISM, as confirmed both in observations of multi-phase gas, as well as in simulations. Such...
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Ms Thando Kekana (University of Johannesburg)30/09/2026, 09:31
We investigate the different modes of energy output from active galactic nuclei (AGN) and their connection to black-hole growth in radio-selected galaxies. To achieve this, we use the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) Early Science catalogue from the COSMOS field observed at 1.28 GHz, which was derived from an image with a median rms of 2 $\mu$Jy beam$^{-1}$....
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Sbongakonke Zondo (University of the Witwatersrand)30/09/2026, 09:52
Hydra A is a FR-I type radio galaxy located at the centre of the Abell 780 cluster with a redshift of z = 0.054. Previous observations of the radio galaxy have been conducted at low frequencies by the Very Large Array (VLA) telescope and using the L-band frequencies of the MeerKAT array telescope. The Chandra X-ray observatory also carried out a detailed survey of the X-ray emission from the...
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Sera Markoff (University of Amsterdam)30/09/2026, 10:30
The Event Horizon Telescope (EHT) is a global mm-VLBI array (230 GHz) that captured the first images of two supermassive black holes, M87 and Sgr A* in 2017. Since then EHT has been expanding with the addition of several new telescopes, as well as a new observing frequency (345 GHz). During its typically annual campaign of ~1-2 weeks, EHT observes the horizon sources as well as a selection...
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DANIEL NGHINYEKWA (University of Namibia)30/09/2026, 11:01
This study aimed to assess existing multi-wavelength analysis techniques and identify statistical mea- sures that effectively characterize temporal variability of blazars. The data used in the analysis were retrieved from VizieR consisting of three catalogs (VLBA, Effelsberg, and Fermi–LAT observations). From these, a sample of 15 common blazars was selected and their light curves were...
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Hartmut Winkler (University of Johannesburg)30/09/2026, 11:14
Fifty years ago local astronomer Tony Fairall initiated what was originally intended as a southern sky counterpart of the Markarian survey. Markarian's observations had led to the identification of many new Active Galactic Nuclei. One of Fairall's first discoveries was a bright nearby quasar that has become known as "Fairall 9". While most of the over 1500 sources added to the Fairall lists in...
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Dr Zahoor Malik (Department of Physics, University of the Free State, Bloemfontein, 9301, South Africa)30/09/2026, 11:27
We investigate the $\gamma$-ray and X-ray population properties of changing-look blazars (CLBs) using sources from the Fourth Fermi-LAT Source Catalog Data Release 4 (4FGL-DR4) together with X-ray information from the Living \textit{Swift} XRT Point Source (LSXPS) catalog. The CLB sample is compared with large populations of confirmed BL Lac objects (BLLs) and flat-spectrum radio quasars...
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Ms Shruti Mukherjee (The University of the Free State)30/09/2026, 11:40
PKS 2155-304 is a nearby high‑synchrotron‑peaked (HSP) BL Lac blazar at redshift z ≈ 0.116, and a benchmark source for studying multiwavelength variability in relativistic jets. In this work, we present a time‑dependent modeling study of its spectral energy distributions (SEDs) across the electromagnetic spectrum, using data from H.E.S.S. (very‑high‑energy gamma rays, 2003-2016), Fermi‑LAT...
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Dr Anna Luashvili (North-West University, Centre for Space Research)30/09/2026, 13:00
Since 2019, the Event Horizon Telescope (EHT) Collaboration released the first horizon-scale images of M87 and Sgr A, two primary EHT targets and the only systems resolved at horizon scales so far, while the innermost jet regions of a few (other) AGNi were explored at an unprecedented angular resolution. EHT campaigns are accompanied by extensive MWL observations, from radio up to...
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Suvas Chaudhary (University of the Free State, Bloemfontein, South Africa.)30/09/2026, 13:31
Blazars are promising sources of extragalactic high-energy astrophysical neutrinos, detected at energies $\gtrsim 10$ TeV by the IceCube neutrino observatory. Here, we report the broadband timing and spectral study of the flat-spectrum radio quasar PKS 1725+123, which has recently emerged as a compelling multimessenger target following its spatial association with the IceCube event IC-201021A....
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Mfuphi Ntshatsha30/09/2026, 13:44
Blazars are a subclass of active galactic nuclei spatially oriented such that our line of sight is closely aligned with their jets. This configuration results in the emissions by relativistic electrons in the jet being Doppler enhanced to higher observed frequencies and luminosities. By contrast, the jets of their parent population, the radio galaxies, point at large angles relative to our...
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Motseothata Tisang30/09/2026, 13:57
Blazars exhibit a characteristic double-humped, non-thermal spectral energy distribution and polarized emission from radio through X-ray energies. While spectral modeling constrains the physical conditions within the emitting region, it does not uniquely constrain the underlying magnetic-field geometry. Polarization provides an additional diagnostic that is sensitive to the projected...
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Mikhail de Villiers (University of Cape Town / South African Astronomical Observatory)30/09/2026, 14:10
Majority of galaxies live in the group environment, which serve as an intermediate galaxy environment between the field and the cluster, making the investigation of the processes involved vital for understanding galaxy evolution. We present MeerKAT observations of the Grus quartet as part of the MeerChoirs survey. The Grus quartet consists of four large spiral galaxies, NGC 7552, NGC 7582, NGC...
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Laenita Lorraine Oberholzer30/09/2026, 14:23
Orphan flares are events where flaring takes place in one frequency
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unaccompanied by flaring in other bands. Orphan flares are usually secondary flares. We study a very-high-energy orphan flare taking place in 3C279, an FSRQ-type blazar. A primary flare was observed 11 days earlier by Fermi-LAT. We study three models that could explain orphan flares. The hadronic synchrotron mirror model,... -
Alexander van der Horst (The George Washington University)30/09/2026, 15:00
Gamma-ray bursts are the most extreme cosmic explosions, emitting across the electromagnetic spectrum and detected on timescales from milliseconds to years. Modeling the multi-wavelength, multi-timescale observations of gamma-ray burst afterglows leads to insights into the macrophysics of the relativistic outflows and their environments, and the microphysics of the particles and magnetic...
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Shain Mukungu (University of Namibia)30/09/2026, 15:31
Searching for transient events in data taken with the transient array radio telescope (TART) is a challenging task. Localising an actual transient event and ruling out that it is not some kind of radio interference source, all without knowing in advance where or when to look, has been the main cause of the challenge. The TART is a low-cost all-sky interferometer of 24 antennas operating at a...
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Ms Lebogang Mfulwane (Centre for Space Research, North-West University,)30/09/2026, 15:44
Fast Radio Bursts (FRBs) are bright, extra-galactic, millisecond-duration transients whose physical origin is still unknown. Luminous compact persistent radio sources (PRSs) have been found to be co-located with a subset of repeating FRBs in some cases. Studying the PRSs may provide clues about the immediate environments of the FRBs, which in turn may reveal the nature of FRB sources. However,...
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Godson Abbey (The Copperbelt University Zambia.)30/09/2026, 15:57
We present a comprehensive multiwavelength afterglow analysis of the nearby LL GRBs GRB~171205A ($z=0.0368$), associated with SN~2017iuk, to constrain its underlying jet structure. Using the standard synchrotron external forward shock framework and Markov Chain Monte Carlo (MCMC) methods, we perform a comparative study of two distinct jet geometries---the canonical top-hat jet and the smoothly...
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Denzel Mkhwanazi (Northwest Univeristy)30/09/2026, 16:10
Gamma-ray bursts (GRBs: seconds to minutes long flashes of gamma-rays, probably resulting
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from either the collapse of a very massive star or from the merger of a neutron star
with another neutron star or a black hole) and jetted active galactic nuclei (in
particular, blazars) are amongst the brightest sources of high-energy gamma-rays in
the Universe. It is well established that the... -
54. Assessing the Impact of Voluntary STEM Teaching in Schools as a Community Development InitiativeBuyisiwe Sondezi (University of Johannesburg, Physics Department, P.O. Box 524, Auckland Park, South Africa, 2006)30/09/2026, 16:30
There are various factors that contribute to the success of learners in the stream of Science, Technology, Engineering and Mathematics (STEM). Considering that these subjects are deemed difficult to most learners and students, most facilitators are constantly seeking and using various methods of teaching these subjects for better outcomes. However, in some cases, external assistance is...
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Prof. Michael Backes (University of Namibia)30/09/2026, 16:31
Blazars constitute the most extreme class of active galactic nuclei (AGN), characterized by relativistic plasma jets oriented directly along the line of sight to Earth. Their multi-wavelength emission displays violent variability across broad electromagnetic bands and diverse time scales, providing crucial probes into relativistic jet dynamics, particle acceleration efficiency, and non-thermal...
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Tristan Jade Wilkinson (University of the Witwatersrand)30/09/2026, 16:32
Axion-like particles (ALPs) are potential dark matter candidates which are proposed as a solution to a problem in the current Standard Model of Particle Physics- the lack of an expected violation of Charge Conjugation & Parity (CP) symmetries. ALPs are strong contenders for dark matter candidates as they interact minimally with both “standard” matter and light, and furthermore are low-energy...
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Banele Mthembu (University of KwaZulu-Natal (National Astrophysics & Space Science Programme))30/09/2026, 16:33
Extended radio galaxies (ERGs) are powerful tracers of galaxy evolution and the interaction between radio jets and their environments. With the sensitivity and resolution of MeerKAT, it is possible to study these radio sources in greater detail than before. This study aims to identify and characterise ERGs in a 1.28 GHz field of the MeerKAT Extended Relics, Giant Halos, and Extragalactic Radio...
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Hambeleleni Davids30/09/2026, 16:34
Globular clusters are established high-energy sources, with their GeV emission generally attributed to unresolved populations of millisecond pulsars (MSPs). However, the physical origin of different components of their broadband spectra remains uncertain. We investigate the emission from 47 Tucanae using a population-scaled, phase-averaged model that combines synchro-curvature radiation from...
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Charles Takalana (IAU-OAD)30/09/2026, 16:35
Galaxy clusters offer an unconventional route to the global 21 cm signal. The low-frequency background passing through the hot intracluster medium is inverse Compton-scattered, producing a cluster-localised spectral distortion, the SZE-21cm, that carries the imprint of the global signal. Since it is measured as a difference between a cluster sightline and nearby blank sky, the effect does not...
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Paul Chitembwa (University of Manchester)30/09/2026, 16:36
Relativistic plasma jets are conduits through which energy, momentum, and angular momentum are transported from the centre of active galactic nuclei (AGNs) to vast distances, extending from sub-parsec to megaparsec scale structures such as hotspots and lobes where they terminate, influencing the so-called AGN feedback processes. Although sufficient energy input is available from jets, both how...
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Mehbuba Ahmed Mohammed (Space Science and Geospatial Institute (SSGI), and 10Academy)30/09/2026, 16:37
The chemical abundance of active galaxies, which host active galactic nuclei (AGN) at their centre, remains poorly studied, most often due to the difficulty of removing the effect of AGN in metallicity measurements. In particular, the chemical abundance of active galaxies in different environments, including clusters and groups of galaxies, is still unknown. In this work, we use a novel HCm...
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Portia Legodi (University of South Africa)30/09/2026, 16:38
We present MeerKAT 1.28 GHz radio-continuum results for the Frontier Field cluster Abell S1063 at $z = 0.351$. The observations reveal a giant radio halo extending over $\sim 1.96$ Mpc, with an integrated flux density of $S_{1.28\,\mathrm{GHz}} = 15.43 \pm 2.73~\mathrm{mJy}$. Its large physical extent and comparatively low radio power place it among the relatively underluminous giant radio...
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Thulo Letsele (Centre for Space Research)30/09/2026, 16:39
In spider pulsar binaries, the energetic pulsar wind continuously ablates the low-mass companion star, driving a complex intrabinary shock and producing a dense local plasma-filled environment. This interaction region acts as a unique laboratory for high-energy astrophysics, yet its precise geometry and local properties remain challenging to constrain. In this work, we present a theoretical...
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B. van SOELEN (Department of Physics University of the Free State Bloemfontein 9301 South Africa), Suvas Chaudhary (University of the Free State, Bloemfontein, South Africa.)30/09/2026, 16:40
Radio galaxies are important laboratories for studying the physics of active galactic nuclei and their relativistic jets. In this study, I will investigate the multi-epoch hard X-ray emission from two nearby radio galaxies, NGC 1275 and Centaurus A. We present a multi-epoch study of the hard X-ray emission from the nearby radio galaxies Centaurus A and NGC 1275 using NuSTAR observations. The...
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Mahike Kilian Kilian (University of the Free State)30/09/2026, 16:41
Gamma-ray binaries are a rare class of high-mass binary systems in which the non-thermal energy spectrum peaks in the gamma-ray regime. PSR B1259-63/LS2883 falls under this rare class and is one of the only three sources where the compact object has been identified as a young pulsar. This system has a 3.4 year orbital period and consists of a 48 ms pulsar and an O9.5 Ve star. The non-thermal...
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Jacques Redelinghuys (University of the Free State)30/09/2026, 16:42
The synchrotron radiation from blazars is produced by populations of relativistic electrons within their jets. This radiation is intrinsically polarized. However, the observed polarization depends strongly on the geometry and physical conditions of the emitting region. It may also be affected by emission from other components, such as contributions from the host galaxy. Thus, connecting the...
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Buyisiwe Sondezi (University of Johannesburg, Physics Department, P.O. Box 524, Auckland Park, South Africa, 2006)30/09/2026, 16:43
Despite the progress in technology that allows many undergraduate experiments in the physical sciences to be simulated, these digital models cannot fully replace the learning benefits of real laboratory work. Hands-on laboratory experiences remain a part of undergraduate science education. They help students build skills, think scientifically, solve problems, and understand the uncertainties...
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Drianca Reddy30/09/2026, 16:44
The Spectral Energy Distribution (SED) of emission produced by blazars, a sub-class of radio-loud Active Galactic Nuclei (AGN), typically exhibits a double-peaked spectrum. The lower-energy peak is attributed to synchrotron emission from relativistic electrons. The origin of the higher-energy peak remains debated and has been modelled by both leptonic and hadronic processes. In this study, we...
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Buyi Sondezi (University of Johannesburg, Chemical Sciences, P.O. Box 524, Auckland Park, 2006)30/09/2026, 16:45
Grounded by constructivism, the study explored students’ understanding of fundamental electrical concepts through hands-on activities involving series and parallel circuits. The study used a pre-post test design to evaluate their conceptual understanding of current, resistance, voltage and the effects of changes in circuits. The evaluation also assessed students’ perceptions of which...
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Andries Mathiba (University of Cape Town)30/09/2026, 16:46
Be X-ray binaries (BeXBs) consist of a compact object, in nearly all known cases a neutron star, in orbit around a massive Oe/Be companion that hosts a quasi-Keplerian equatorial decretion disc. This disc is the reservoir from which the compact object accretes, and its geometry, density and dynamical state set the conditions for X-ray outburst triggering, amplitude and recurrence. Despite...
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Spencer Tendai Madzime30/09/2026, 16:47
We present a search for transient gamma-ray activity from the rapidly rotating, highly magnetized white dwarf ZTF J1901+1458 using Fermi-LAT data. We investigate the temporal behaviour of the source by analysing individual time intervals and identify several candidate episodes with test statistics corresponding approximately to the (3\sigma) significance regime. The candidate intervals show...
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23. Gamma-Ray Bursts redshift estimators and the connection between GRB rate and Star Formation rateMaria Dainotti (Stanford University)01/10/2026, 08:30
Gamma-ray bursts (GRBs) can be probes of the early Universe, but currently, only 26% of GRBs observed by the Neil Gehrels Swift Observatory have known redshifts (z) due to observational limitations. To address this, we estimated the GRB redshift (distance) via a supervised statistical learning model that uses optical afterglow observed by Swift and ground-based telescopes. The inferred...
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Prof. Christo Venter (North-West University), Shruti Bhatporia (North-West University)01/10/2026, 09:01
The statistical characterization of Fast Radio Burst (FRB) populations is fundamentally constrained by selection biases and the non-linear coupling of intrinsic source physics with extrinsic propagation effects. A primary hurdle is the DM-z degeneracy, where unknown host galaxy dispersion ($DM_{host}$) obscures cosmological distances. This is further compounded by morphological smearing;...
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Dr ankur ghosh (University of Johannesburg)01/10/2026, 09:14
Short gamma-ray bursts (sGRBs) are associated with compact binary mergers, as established by the joint detection of GW 170817 and GRB 170817A, although the nature of the post-merger remnant remains uncertain. A long-lived millisecond magnetar provides a possible central engine for the extended X-ray emission observed in a fraction of sGRBs. We investigate nine sGRBs detected between 2016 and...
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Gesesew Reta Habtie (Debre Berhan University)01/10/2026, 09:27
This paper presents the findings from our study of nova V1405 Cas over the first 1051 days after the outburst. The study includes an analysis of the photometric light-curve evolution, along with a detailed spectroscopic analysis. Photometric analysis shows that the nova is a very slow nova, with a decline timescale of t2 ≈ 165 days. The mass of the white dwarf (WD) is calculated as MWD ∼ 0.7...
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Soebur Razzaque01/10/2026, 09:40
Phenomenological relations between the isotropic energy and spectral peak energy in the source rest frame (the Amati relation) and between the isotropic luminosity and spectral peak energy in the source rest frame (the Yonetoku relation) in gamma-ray bursts have been widely conjectured as potential cosmological standard candles. However, reliably using these relations as standard candles...
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Tamador Aldowma (Johannesburg University, Omdurman Islamic University)01/10/2026, 10:30
Gamma-ray bursts (GRBs) can extend cosmological studies beyond the redshift range of Type Ia supernovae (SNe Ia), but their calibration is affected by the circularity problem. We apply LADDER, a deep-learning reconstruction trained on Pantheon+ SNe Ia, to obtain a model-independent distance-redshift relation. Building a self-contained calibration pipeline applied directly to raw Fermi-GBM...
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Saeeda Sajjad (Theoretical Research Institute, Pakistan Academy of Sciences (TRIPAS), Pakistan, Centre for Astro-Particle Physics (CAPP), University of Johannesburg, South Africa)01/10/2026, 10:43
Machine learning approaches based on the Fermi GBM catalogue data typically use parameters such as the duration of the bursts, its fluence or flux along with various parameters obtained from spectral fits. These approaches typically ignore the error on the spectral parameters. Yet, these errors also contain information about the GRB. In this work, we use the errors on the spectral parameters...
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Athira M Bharathan (North-West University, South Africa)01/10/2026, 10:561Multi-Messenger Astrophysics and Astro-Particle PhysicsContributed Talk
The flat-spectrum radio quasar PKS~0215+015 ($z \simeq 1.715$) was found to be positionally and temporally coincident with the IceCube neutrino event IceCube-220225A, detected on 25~February~2022 with a reconstructed energy of $\sim$154~TeV. The source was the only $\gamma$-ray emitter within the 90\% neutrino localisation region and was independently confirmed to be in an elevated...
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Geoff Beck01/10/2026, 11:09Multi-Messenger Astrophysics and Astro-Particle PhysicsContributed Talk
Indirect dark matter searches have historically concentrated on the nearby universe. In this work we explore whether higher redshift objects $z \gtrsim 0.1$ could be an under-utilised resource in the search for the fundamental nature of dark matter. We do so by exploring MeerKAT observations of higher redshift galaxy clusters and considering current and future gamma-ray experiment...
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Khushboo Dixit01/10/2026, 11:22Multi-Messenger Astrophysics and Astro-Particle PhysicsContributed Talk
High-energy astrophysical messengers provide a unique probe of possible non-gravitational interactions of dark matter. In particular, gamma rays produced in the vicinity of supermassive black holes may traverse large dark-matter column densities, especially in the presence of dense dark-matter spikes, and can consequently be attenuated through dark matter–photon scattering. In this work, we...
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Mpho Kgoadi (University of the Witwatersrand)02/10/2026, 09:00
The anomalously fast orbital decay of the black hole X-ray binaries A0620−00 and XTE J1118+480 has been attributed to dynamical friction in dark matter density spikes, and annihilation within these spikes has recently been proposed as the origin of the high-energy positron excess measured by AMS-02. That proposal treats positron propagation using interstellar conditions throughout, neglecting...
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Dr Lutendo Nyadzani (University of Johannesburg)02/10/2026, 09:13
Accretion onto the first-born neutron star during a super-Eddington episode has been proposed as one of the formation channels of the most massive neutron stars in the gravitational-wave catalogue, notably the components of GW190425. In this work, we examine the transfer of material from the outer disc to the stellar surface during the super-Eddington phase. We take into account the disc...
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Itumeleng Monageng02/10/2026, 09:26
Be X-ray binaries, which constitute the largest subclass of high-mass X-ray binary systems, consist of a neutron star in an eccentric orbit around a Be star companion, accompanied by a geometrically thin Keplerian disc. These systems are strong candidates for being progenitors of gravitational waves, as their evolutionary process can ultimately lead to the formation of a binary system...
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David Buckley (South African Astronomical Observatory)02/10/2026, 09:39
The study of the dynamic Universe is entering a new era of time-domain, multi-wavelength and multi-messenger astronomy. High-energy transients provide unique probes of black-hole accretion, compact objects, stellar explosions and the early Universe, while electromagnetic counterparts to gravitational-wave and neutrino events offer new opportunities for understanding the most energetic cosmic...
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Hiiko Katjaita (University of Namibia)02/10/2026, 09:52
The Africa Millimetre Telescope (AMT), planned for construction in Namibia, will expand Africa’s contribution to millimetre very-long-baseline interferometry (VLBI) and the Event Horizon Telescope (EHT), supporting future EHT and multi-wavelength studies of supermassive black holes, accretion flows, and relativistic jets. Its ability to participate effectively in EHT observations will depend...
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Dr Jeandrew Brink (University of the Free State)02/10/2026, 10:30
This talk proposes using resonant structures around a Kerr black hole as a model agnostic means of quantifying departures from the Kerr Metric. Initial observational evidence that these structure exist around Sgr A* is presented.
When a black hole is immersed into an astrophysical environment, the KAM theorem predicts that the spacetime geodesic structure will exhibit non-smooth...
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Keith McPherson02/10/2026, 11:01
Using multiple theoretical emission models, the flux density of dwarf novae can be modelled. These sources can emit light from radio frequencies up to x-ray frequencies. Using various theoretical models, we can gain insight on the parameters of these sources. For this study, RU Pegasi, IP Pegasi, and V426 Ophiuchi were selected as they were detected by the MeerKAT telescope during outburst....
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Mr Erik Van Vuuren (University of the Freestate)02/10/2026, 11:14
V1223 Sagittarii is an intermediate polar (IP), a subclass of magnetic cataclysmic variables containing an accreting white dwarf(WD) with a magnetic fields ranging between(0.5-8) MG. Optical and x-ray observations have established an orbital period of approximately 3.366 hr and a WD spin period of approximately 12.4 min. Additionally, a 13.2 min beat period, arising from the interaction...
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Prof. Roger Deane (IDIA / University of Cape Town)02/10/2026, 11:27
I will present an overview and report early science from the MeerKAT-South Pole Telescope (SPT) Survey, a deep MeerKAT UHF-band eXtra Large Project (XLP) legacy project recently approved to map 800 square degrees of the southern sky to a sensitivity of ~10 uJy/beam. Uniquely designed to exploit the synergy between world-leading observatories at ~1 GHz and ~100 GHz, this survey covers the...
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Spencer Tendai Madzime (University of the Free State)02/10/2026, 11:40
We present a reanalysis of the \textit{Fermi}-LAT data of V1674 Her, a rapidly rotating intermediate polar with GeV $\gamma$-ray emission first detected during its 2021 nova outburst. Previous interpretations of the $\gamma$-ray emission from V1674 Her have primarily invoked particle acceleration in shocks associated with the nova ejecta. Here, we investigate the temporal and spectral...
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PATRICK OKEZUONU (ABIA STATE UNIVERSITY, UTURU)02/10/2026, 11:53
Energetic feedback from massive young stars can modify the same magnetic structures that regulate gravitational collapse, yet the observational connection between feedback-driven magnetic restructuring and star-formation efficiency (SFE) remains poorly constrained. We investigate 11 high-mass Galactic star-forming regions observed with the James Clerk Maxwell Telescope (JCMT), combining...
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Yusuke Tampo (South African Astronomical Observatory)02/10/2026, 13:00Other High-Energy SourcesContributed Talk
Accretion discs experience various kinds of instabilities, observed as energetic events in our Universe. Compact binaries especially offer a unique opportunity to study these instabilities as transient phenomena. Here we report optical studies of the cataclysmic variable CM Mic, characterized by highly frequent dwarf nova outbursts driven by thermal-viscous instability and occasional...
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Nikita Rawat (South African Astronomical Observatory)02/10/2026, 13:13Other High-Energy SourcesContributed Talk
Attached.
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Eli Kasai (University of Namibia)02/10/2026, 13:26Active Galactic NucleiContributed Talk
We present initial efforts towards the construction of a catalogue of frequency- and timescale-dependent variability properties of blazars observed as flux calibrators with the Atacama Large Millimeter/submillimeter Array (ALMA), exploiting multi-epoch observations spanning Bands 3–10. Multi-epoch light curves are constructed for suitably sampled sources, from which complementary variability...
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Joshua Robinson (North-West University)02/10/2026, 13:39Active Galactic NucleiContributed Talk
In this work, we demonstrate the application of the Gammapy Python package for simultaneous multi-wavelength spectral fitting of low level data across multiple energy decades. We have integrated the B13 lepto-hadronic emission code into the Gammapy framework, enabling comprehensive multi-instrument data analysis. Additionally, we incorporate IceCube neutrino detector response functions based...
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Izak van der Westhuizen02/10/2026, 13:52Active Galactic NucleiContributed Talk
Blazars are a subclass of Active Galactic Nuclei (AGN) that contain relativistic jets oriented towards the observer. The Spectral Energy Distribution (SED) of these sources are typically dominated by two broad non-thermal components. The lower-energy component is produced by synchrotron emission from relativistic electrons in the jet, while the high-energy component can be a combination of...
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Charles Takalana (IAU-OAD), Dr Joyful Mdhluli (IAU-OAD)02/10/2026, 14:05Outreach and EducationContributed Talk
For over a century, the International Astronomical Union (IAU) has promoted and safeguarded astronomy worldwide through its Office of Astronomy for Development (OAD), hosted in South Africa by the National Research Foundation (NRF) and supported by the South African Department of Science, Technology, and Innovation (DSTI). The OAD has established a network of 11 regional offices globally and...
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Prof. Buyi Sondezi (Rare Earth-Based Oxides and Nano Group, Department of Physics, University of Johannesburg, Cnr Kingsway Avenue and University Road, Auckland Park 2006, South Africa)02/10/2026, 15:00
Friendly learning environments have been widely explored for their potential to enhance students’ understanding of fundamental Physics concepts and improve cognitive achievement. This is particularly significant given the widespread perception of Physics as a challenging subject, especially among first-year university students. During this critical transition period, many students encounter...
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Meryem Guennoun (African Astronomical Society)02/10/2026, 15:13
Astronomy has a unique ability to inspire curiosity, strengthen scientific literacy, and engage diverse audiences across cultures and generations. While many outreach initiatives are implemented at local or national levels, coordinating science communication at a continental scale presents both unique opportunities and significant challenges.
The African Astronomical Society (AfAS), as the...
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Dr Monica Barnard (Centre for Space Research, North-West University, Potchefstroom 2520, South Africa)02/10/2026, 15:26
We model curvature radiation from primary particles accelerated in a dissipative magnetosphere, within an extended separatrix region leading into the current sheet outside the light cylinder, using the azimuthally-dependent electric field from global magnetospheric simulations. This serves as a step towards a full synchro-curvature treatment of the Vela pulsar's high-energy emission observed...
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Dr Debabrata Deb (Centre for Space Research, North-West University)02/10/2026, 15:39
Pulsars provide exceptionally stable astrophysical clocks, but precision timing at low radio frequencies is complicated by changes in their observed pulse profiles across the observing band. Such frequency-dependent profile evolution can introduce systematic offsets in measured pulse arrival times if a single frequency-averaged template is used. We investigate how frequency resolution can be...
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Christo Venter02/10/2026, 15:52
Recent detections of pulsed very-high-energy (VHE) emission from PSR B1706−44, Geminga, the Crab, and Vela by ground-based Cherenkov telescopes have prompted renewed efforts to refine models of high-energy pulsar emission. Of particular interest is the discovery of a distinct TeV spectral component in Vela, separate from its GeV component and unlike the spectral behaviour observed in other...
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Ms Dimakatso Maheso02/10/2026, 16:05
Radio emission from pulsars is commonly modelled as a core and cone beam, since this decomposition reasonably reproduces the single, double, and multiple-component pulse profiles observed across the pulsar population, unlike a simple single-beam model. This structure is usually modelled within a vacuum dipole magnetic field. However, this is inconsistent with the more modern force-free...
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Luyanda Mazwi (University of Johannesburg (Centre for Astro-Particle Physics))02/10/2026, 16:18
Intermediate-mass black holes, spanning 10²–10⁵ solar masses, are the missing link between stellar-mass and supermassive black holes, and no unambiguous example is known in the Milky Way. We search for intermediate-mass black holes along 83 southern sightlines, using the MeerKAT Pulsar Timing Array 4.5-year data release as an array of independent accelerometers. A free-floating IMBH near a...
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Paul Chitembwa (University of Manchester)Active Galactic NucleiPoster
Relativistic plasma jets are conduits through which energy, momentum, and angular momentum are transported from the centre of active galactic nuclei (AGNs) to vast distances, extending from sub-parsec to megaparsec scale structures such as hotspots and lobes where they terminate, influencing the so-called AGN feedback processes. Although sufficient energy input is available from jets, both how...
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