Conveners
Science & Engineering: 1 Cosmology
- Kavilan Moodley (University of KwaZulu-Natal)
Science & Engineering: 2 Instrumentation & Other
- Brian Chaboyer (Dartmouth College and SALT)
Science & Engineering: 3 Galaxies I
- Christopher Conselice (Manchester University, England (UK))
Science & Engineering: 4 Galaxies II
- Jacobus Diener (BIUST)
Science & Engineering: 5 Transients
- David Buckley (South African Astronomical Observatory)
Science & Engineering: 6 Galaxy Clusters
- Mirjana Povic (IAA-CSIC (Spain) and SSGI (Ethiopia))
Science & Engineering: 7 Stars and Star Formation I
- James Chibueze (University of South Africa)
Science & Engineering: 8 Stars and Star Formation II
- Matipon Tangmatitham
Science & Engineering: 9 Machine Learning and Techniques
- Nadeem Oozeer (SARAO)
Previous studies of galaxy formation have shown that only 10 per cent of the cosmic baryons are in stars and galaxies, while 90 per cent of them are missing. In this talk, I will present three observational studies that coherently find significant evidences of the missing baryons. The first is the cross-correlation between the kinetic Sunyaev-Zeldovich maps from Planck with the linear...
This study investigates the formation of non-linear ion-acoustic solitary structures (IASSs) in magnetized plasmas consisting of inertial cold ions, superthermal electrons, and positrons. The reductive perturbation method was employed to derive the Korteweg-de Vries (KdV) equation, and the steady state solution of the KdV equation was obtained, providing a framework for exploring the solitary...
Gravitational lensing provides a powerful probe of the global mass properties of galaxies, which are best tested using observations at extremely high angular resolution. In addition, through detailed observations of the lensed images, it is possible to place tight constraints on the nature of dark matter through measuring the abundance and properties of low mass haloes via their subtle...
Interacting Dark Energy (IDE) models, where dark matter and dark energy interact through a non-gravitational coupling, have recently regained attention as late-time cosmic tensions persist and new datasets hint at possible dynamical dark energy and deviations from ΛCDM.
In this talk, we will present observational constraints on a broad class of linear and non-linear IDE models using some of...
We study cosmic magnification beyond lensing in a late-time universe dominated by quintessence and cold dark matter. The cosmic magnification angular power spectrum, especially going beyond the well-known lensing effect, provides an independent avenue for investigating the properties of quintessence, and hence, dark energy. By analysing the magnification power spectrum at different redshifts,...
The redshifted 21 cm line is a powerful probe of the epoch when the first stars and galaxies were born and, consequently, reionized the intergalactic medium. In this talk I will present upper limits on the redshifted 21 cm line obtained through observations with the Hydrogen Epoch of Reionization Array showing that the intergalacticm medium was heated above the adiabatic limit before z ~ 8. I...
A new method for optimizing the layout of radio telescope antenna arrays will be presented. These methods are are based on the SVD of the telescope operator, and provide a flexible method for choosing optimal antenna positions. The method is applied to choosed antenna positions for the TART telescope, and this has led to the latest spiral antenna designs used in the African TART telescopes in...
Since 1907, a lot of valuable and important scientific research work has been done using the 30-inch Reynolds refractor at Helwan, and Kottamia 74-inch telescope in Egypt. Kottamia telescope is the only one at its size in the Middle East and the second in Africa.
In my talk, the Egyptian current observatory facilities will be presented. The talk will be somewhat technical and is related to...
Small near-Earth asteroids (NEAs $<$ 150m) represent the most numerous yet least understood segment of potentially hazardous objects in our Solar System. Their rapid fading after discovery makes it challenging to obtain sufficient follow-up observations for characterisation studies, leaving a critical gap in our knowledge of their taxonomic distribution. We present results from a robotic...
The study emphasizes a switchable characteristic of narrow-band coupled resonators of a dual-band filter developed based on the reactance transformation method as a single filter structure. The filter is realized on Mercurywave 9350 multi-layer substrate. The substrate was chosen for various reasons, including its relatively constant permittivity over frequency. The designs feature a dual-path...
MeerKLASS is a single dish HI intensity mapping survey of the MeerKAT Telescope. Probing the 21 cm signal is coupled with challenges from foregrounds and radio frequency interferences (RFI) which contaminates the data, and in turn our cosmological signal. The MeerKLASS collaboration has produced a detection of the HI cosmological signal using cross-correlations with galaxy surveys. However,...
Computational methods underpin much of modern research, yet authors of these methods have not always received appropriate credit for their work, and locating reliable, reusable software can be challenging for both researchers and students. The Astrophysics Source Code Library (ASCL; ascl.net) addresses these issues by providing a free, curated registry of openly available software used in...
Quasars have historically been classified into two distinct classes, radio-loud (RL) and radio-quiet (RQ), taking into account the presence and absence of relativistic radio jets, respectively. Although different attempts were made to unify these two classes, there is a long-standing open debate involving the possibility of a real physical dichotomy between RL and RQ quasars. To address this,...
One of the fundamental challenges in understanding dwarf irregular galaxies is determining how their HI structure and kinematics influence their star formation activity and dark matter distribution. The MHONGOOSE survey, using deep MeerKAT observations, provides an unprecedented opportunity to study these processes in detail. In this talk, I will present an analysis of the HI distribution,...
Within the MIGHTEE deep continuum images, we discovered one of the rarest subpopulations of radio galaxies (RGs) called triple-double radio galaxies (TDRGs). They are characterised by three pairs of radio lobes, each pair of lobes representing an episode of nuclear activity. TDRGs are key tools to understand the duty cycle of RGs. In this work, we report the seventh known TDRG, J022248−060934....
Understanding the co-evolution of supermassive black holes and star formation remains a fundamental challenge in galaxy evolution studies. Radio emission in galaxies is often a complex mixture of star formation and Active Galactic Nuclei (AGN) activity, requiring milli-arcsecond resolution to disentangle. We present the first results from the VLBI Lockman Hole Survey, a deep wide-field...
Understanding the origin and working modes of the cessation of star formation in galaxies that lead to the passively evolving population is vital in galaxy evolution studies. The environment of galaxies is a critical aspect of these investigations, as the fraction of star-forming galaxies is the lowest inside galaxy clusters. At the same time, the fraction of passive galaxies is the highest....
We present deep MeerKAT follow-up observations (16 hrs with the 32k correlator) of an extraordinary, extremely low column-density HI disk uncovered in the SARAO MeerKAT Galactic Plane Survey (SMGPS). MeerKAT reveals a vast, patchy, spiral-like structure dominated by exceptionally low column densities (10^18 – 10^20/cm^2). Despite its modest HI mass, the disk reaches an astonishing ~260...
Blazars, a subclass of active galactic nuclei (AGN) with relativistic jets aligned close to our line of sight, dominate the extragalactic gamma-ray sky and are characterised by pronounced variability across the electromagnetic spectrum. Millimetre observations are particularly valuable as they probe emission regions close to the base of the jet, where high-energy activity is thought to...
The current ∧CDM model of hierarchical galaxy formation highlights the importance of galaxy
interactions and mergers in the evolution of galaxies. Galaxies undergo cycles of star forma-
tion and AGN activity induced by mergers and interactions as they evolve towards early-type
quiescent objects. However, this has not been observationally well supported. In this work, we
aim to go a step...
I describe the cosmic evolution of galaxy discs from z~6 to the present using bars as a sign post of galaxy evolution. I will describe the observations and analysis from two fundamental surveys I have led, namely COSMOS and S4G which together form the foundational datasets for the study of galactic structure from high redshifts to the local Universe. We find that galaxy disk assembly and...
We present a kinematic and mass-modelling analysis of the nearby late-type galaxy NGC 45 using high-quality HI observations from the IMAGINE survey, complemented by a stellar mass profile derived from Spitzer IRAC 1 (3.6 μm) imaging. From the well-resolved HI cube, we construct a rotation curve and decompose it into stellar, gaseous, and dark matter (DM) components. Mass models are fitted...
Angular momentum is a fundamental property that shapes the evolution of disc galaxies, strongly influencing the internal mechanisms that regulate star formation. In an ideally closed system, angular momentum would be conserved; however, because galaxies continuously interact with their environments, their angular momentum content is expected to change over time. Despite extensive work, a clear...
The origin and impact of radio emission in radio-quiet quasars has remained ambiguous for decades, largely due to limitations of all-sky, low-resolution surveys. Leveraging new, sensitive sub-kpc–to–kpc scale radio imaging from the Quasar Feedback Survey (QFeedS), we are now resolving the structures that drive feedback at the heart of massive galaxies. Using e-MERLIN, we mapped radio emission...
The second data release (DR2) of the Indian Pulsar Timing Array (InPTA) represents a major milestone in precision pulsar timing using the upgraded Giant Metrewave Radio Telescope (uGMRT). Combining seven years of simultaneous dual-band observations (300–500 MHz and 1260–1460 MHz) of 27 millisecond pulsars (MSPs), InPTA DR2 provides one of the most sensitive low-frequency datasets currently...
Stellar occultations, in which an asteroid transits across the line of sight to a background star, provide one of the most accurate ground-based methods for determining asteroid diameters, shapes, and possible companions. This study reports on a series of predicted asteroid occultation events monitored using the 1.88-m Kottamia Telescope in Egypt. High-cadence CCD imaging and photometric...
Massive X-ray binaries are intriguing astrophysical systems that provide valuable insights into some of the most extreme physical processes in the universe. These binary systems offer a unique opportunity to study the end products of stellar evolution, specifically neutron stars and black holes. As precursors to gravitational waves and short gamma-ray bursts, massive X-ray binaries are...
We present a detailed single-pulse study of the long-period pulsar PSR J2129+4119 using high-sensitivity FAST observations. Despite locating well below the traditional death line, the pulsar exhibits sustained and multi-modal emission behavior, including nulls, weak pulses, regular emission, and occasional bright pulses. The nulling fraction is measured to be $8.13\% \pm 0.51\%$, with null...
Fast Radio Bursts (FRBs) are bright, millisecond radio pulses occurring at cosmological distances. The nature of these sources is still unknown. Upon localisation of the repeating FRBs, luminous compact persistent radio sources (PRSs) can be detected in some cases. Studying the PRSs may give us clues about the immediate environments of the FRBs, which in turn provides insights into the nature...
We present a rigorous extension of the multi-tracer power spectrum
formalism to a three-tracer framework, systematically deriving the covariance and Fisher information matrices for three distinct biased tracers. Applied to a joint analysis of the DESI Bright Galaxy Survey, the HI Galaxy
Survey, and SKA1-Band2 intensity mapping, the formalism incorporates
redshift-space distortions and...
We present MeerKAT HI observations of galaxies in the core of the Shapley Supercluster, one of the most massive structures in the local Universe. Our sample of HI-detected galaxies in A3558 and SC1329 allows us to examine how cold-gas content and star formation evolve in an extreme, high-density environment. Galaxies in the SSC-core lie systematically below field HI scaling relations, showing...
Galaxy clusters are the largest gravitationally bound structures in the universe, hosting megaparsec-scale diffuse radio emission in the form of halos and relics. These non-thermal synchrotron sources trace shocks, turbulence, and magnetic fields in the intracluster medium, providing a unique window into particle acceleration processes and cosmic magnetism. The upcoming Square Kilometre Array...
Galaxy groups and clusters retain a fossil record of their formation history in the chemical composition of their hot intragroup and intracluster gas. Upcoming high-resolution X-ray missions, such as Athena’s X-IFU, will provide spatially resolved abundance measurements for multiple elements. In this work, I combine the cosmological hydrodynamical simulation Simba-C, which incorporates the...
The formation and evolution of the Milky Way has been a long-standing subject of interest. Stars in the thick and thin disc components overlap in the intermediate-age regime, unlike at the extreme ends of the metallicity versus alpha-abundance spectrum, where both populations are well separated. In this study, we introduce a new technique that utilises the [Na/Fe] versus stellar age relation...
We present preliminary results from a study of 13 mini-halos (MHs), including candidate sources from the MeerKAT Galaxy Cluster Legacy Survey (MGCLS). Mini-halos are diffuse, faint radio sources typically found in relaxed galaxy clusters, with their origins attributed to either hadronic interactions or turbulent re-acceleration processes. Using \texttt{oxkat}, we reduced archival L-band MGCLS...
This project conducts a comparative analysis of galaxies in the Fornax
main cluster and its Fornax A subcluster. Dominated by NGC 1399,
Fornax is the most massive southern hemisphere cluster within 20Mpc.
The NGC 1316 subcluster, gravitationally bound and potentially on its
first infall, exhibits intense star formation, providing a unique laboratory
to study how cluster assembly affects...
Full Stokes polarisation measurements of a sample of star-forming regions have been observed in the C-band with the Green Bank 100m telescope. Results of the polarisation properties of the detected 4.7 and 6.0 GHz excited OH masers will be reported, and what can be inferred about the magnetic fields in these regions. Besides the masers, there is also some thermal emission from some of these...
New CCD light curves in the V, Rc, and Ic bands of the W UMa-type eclipsing binary system KAO-EGYPT J214258.21+440520.2 were obtained using the 1.88 m reflector telescope at Kottamia Astronomical Observatory (KAO), Egypt, on September 27 and 28, 2016. Based on these observations, new times of minima and a revised ephemeris have been determined. The geometric and photometric parameters of the...
In this presentation we are going to develops mathematical equations which explain how stellar oscillations interact with convection. The research defines essential mathematical components needed to model stellar oscillation responses to convective effects through the integration of linearized pulsation equations (momentum, continuity, and energy) with Mixing-Length Theory equations for...
We present a multi-wavelength analysis of the massive star-forming region G345.50+0.35 using MeerKAT observations and high-resolution ALMA archival data to investigate the morphology, kinematics, and dynamical ages of gas and dust in this region. Ionized gas traced by free–free emission reveals three sources labelled A, B, and C with source C exhibiting a morphology indicative of triggered...
Interacting galaxies provide the critical mechanism for linking young massive star clusters (YMCs) and neutral hydrogen (HI): the intense starbursts they trigger form YMCs, and the subsequent stellar feedback from these clusters (e.g., stellar winds, supernovae) dramatically sculpts the surrounding HI gas. This impact of stellar feedback on the HI distribution and kinematics is a critical, yet...
ESA’s PLATO mission will provide highly precise photometric data, necessitating equally accurate and consistent spectroscopic information to precisely characterise stars and their orbiting planets. Currently, many gas-giant exoplanet host stars in the PLATO southern prime field designated for the mission lack uniformly derived atmospheric and chemical parameters. This inconsistency in...
We investigate the periodic variability of 6.7 GHz class II methanol masers in the high-mass star-forming region G174.20-0.08 using multi-epoch observations from the Hartebeesthoek Radio Astronomy Observatory (HartRAO). These masers trace dynamic processes near massive protostars. Our analysis reveals repeating flux variations, possibly linked to accretion bursts, binary motion, or disk...
We present high-resolution S-band (3.1GHz) radio continuum observations of eleven massive young stellar objects (MYSOs), most of which exhibited extended emission in the SARAO MeerKAT Galactic Plane Survey conducted at 1.3GHz. The improved angular resolution of ∼3.1" at 3.1GHz enabled the detection of all the jets with many resolved in to multiple components, allowing detailed analysis of...
Star formation is a multi-scale process which is regulated by many different environmental factors. Gravity, global and local gas dynamics, radiation and feedback processes, turbulence and magnetic fields all play a role in regulating star formation rates and the resulting star population. We attempt to further constrain the ‘star formation recipe’ by determining how the large-scale dynamics...
Zeeman splitting observed from maser line profiles, enables the line-of-sight magnetic field magnitude to be ascertained. And the maser’s linear polarization position angle provides the magnetic field orientation in the reference-frame perpendicular to the observer. This detail, together with changing maser linear and circular polarization, has facilitated the creation of model where we are...
Globular clusters are among the most well-studied objects in astronomy (Renaud, 2018). The continued study thereof will likely reveal key insights into the spatial, dynamical and chemical properties of galaxies (particularly the Milky Way), stellar formation and evolution, as well as assist in applying constraints on dark matter and initial mass function models.
My Master’s project was...
Telescopes such as the Square Kilometre Array (SKA) and Vera C. Rubin Observatory (LSSRT) will produce more data than astronomers can analyse manually. Machine learning, being data-driven, is increasingly being applied in astronomy. Unsupervised machine learning, in particular, is a powerful approach for finding patterns and anomalies automatically, but struggles with high-dimensional data...
Astronomical seeing refers to the clarity and sharpness of celestial observations, governed largely by atmospheric turbulence influenced by dust, humidity, wind, and temperature fluctuations. Poor seeing conditions distort images, degrade measurement accuracy, and lead to inefficient use of valuable telescope time. These atmospheric fluctuations also critically affect geodetic systems such as...
We introduce OJALA (Optimizing J-PAS Astronomy for Large-scale Analysis), a Transformer-based foundation model specifically designed to analyze narrow-band photometry from the Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS). The model is pre-trained on synthetic photometry derived from 19.6 million spectra from the Dark Energy Spectroscopic Instrument (DESI)....
Hyperspectral satellite missions create opportunities for plant health monitoring from space. The German Environmental Mapping and Analysis Program (EnMAP) is a spaceborne hyperspectral mission that provides dense spectral coverage for each ground pixel. This study proposes to use EnMAP data for plant pest and disease detection, an application area that remains largely unexplored. Previous...