RATT Postgraduate Scholarships
and Research Projects For 2026
(Applications for 2026 are now closed)
RATT invites applicants for postgraduate scholarships commencing in 2026. We have a mix of science-oriented and techniques-oriented projects – some may fall into both categories, depending on scope. Note that a number of our projects are also eligible for funding via SARAO freestanding bursaries, these are marked by “(SARAO)” below, and the project text includes a link to a more detailed project description on the SARAO website. The funding levels and the application process are the same for all categories of funding.
The Rhodes internal closing date for applications will be announced soon, please keep an eye on the Rhodes Postgraduate Funding site. Please allow yourself ample time for the application process.
List Of Projects
(PhD) (SARAO) MERGHERS Dynamics: Probing the merger state of galaxy clusters
(PhD) (SARAO) Studying diffuse cluster emission evolution with MERGHERS
(PhD) (SARAO) Probing formation mechanisms of MGCLS radio halos
(PhD) (SARAO) The Neutral Hydrogen Gas in Galaxy Clusters
(PhD) (SARAO) Mining the MeerKAT archive for RS CVn stellar flares and other transients
(PhD) (SARAO) Observations of the Universe first (radio) light with HERA
(PhD) Galaxy Evolution Across Environments with MeerKAT
(MSc / PhD) Galaxy cluster stacking studies with SKAO Precursor telescopes
(MSc) (SARAO) Quantifying HI Morphologies
(MSc) (SARAO) A MIGHTEE chromatic view of galaxy evolution
(MSc) (SARAO) Exploring the merger dynamics of the SPT-CL J2031-4037 cluster
(MSc) (SARAO) Spectral study of the diffuse radio source in the Abell 2443 cluster
(MSc) (SARAO) Investigating Odd Radio Circles in the Shapley Supercluster
(MSc) Development of a Wideband Printed Log-Periodic Dipole Array for EMC Metrology
(MSc) (SARAO) Upgrading the Rhodes University Transient Array Radio Telescope (RUTART)
Supervisors: Dr Kenda Knowles (k.knowles@ru.ac.za)
Prof Matt Hilton (U. Witwatersrand)
This PhD project aims to use existing X-ray imaging and optical photometry/spectroscopy to determine the dynamical state of more than 30 Sunyaev-Zel’dovich-selected galaxy clusters observed as part of the MeerKAT Exploration of Relics, Giant Halos, and Extragalactic Radio Sources (MERGHERS) survey. The dynamical state is necessary to accurately characterise diffuse radio emission in the clusters and to interrogate and understand non-detections. The multiwavelength data also allows the interrogation of relevant merger dynamics, crucial for understanding the formation of the diffuse radio sources. The project is expected to produce at least one student-led paper. Link to the full project description here. This project has dedicated funding through the Rhodes University/SARAO Group Grant.
Supervisors: Dr Kenda Knowles (k.knowles@ru.ac.za)
Dr Virginia Cuciti (INAF Bologna)
This PhD project aims to study the cosmic evolution of diffuse cluster radio emission using cluster data from the MeerKAT Exploration of Relics, Giant Halos, and Extragalactic Radio Sources (MERGHERS) survey. With the majority of statistical samples in the literature restricted to low redshift systems, probing the higher redshift phase space in a systematic way is crucial to probing the evolutionary properties of the radio sources and the physical mechanisms which drive them. The project will perform a statistical study of the first two tiers of MERGHERS clusters (56 targets at mid-to-high redshift) and compare to literature data to probe the redshift evolution of diffuse cluster emission. Link to the full project description here.
Supervisors: Dr Kenda Knowles (k.knowles@ru.ac.za)
Dr Sinenhlanhla Sikhosana (UKZN, sikhosanas@ukzn.ac.za)
Different radio halo formation scenarios predict different slopes in the point-to-point non-thermal vs thermal ICM correlations. We will use archival X-ray data to study the point to point correlation for MGCLS radio halos in order to constrain the formation mechanism at play in the different clusters, and compare the results with the multiwavelength view of the cluster mergers to determine if different formation models produce distinguishable merger characteristics. This project is expected to produce at least one publication. Link to the full project description here.
Supervisors: Dr Mpati Ramatsoku (m.ramatsoku@ru.ac.za)
Dr. Gyula I. G. Józsa (gjozsa@mpifr-bonn.mpg.de)
Prof Oleg Smirnov (osmirnov@gmail.com)
Broadly speaking, galaxies can be divided into two main types: actively star-forming (blue) spiral and irregular galaxies, and early-type galaxies, which are no longer forming stars, appear red and mostly structureless, and are considered ‘dead’ because they have lost their star-forming material—the gas. It is clear that galaxies must undergo a transition from star-forming to non-star-forming, and potentially vice-versa, depending mainly on environmental effects. Larger star-forming galaxies, in particular, need to accrete gas from their surroundings to sustain star formation, as their internal gas reservoirs are insufficient to fuel star formation over their lifetime. At the same time, external processes can strip galaxies of their gas, halting star formation and transforming them into early-type galaxies.
A good understanding of these processes is important to support cosmological theories and simulations. It is well-established that galaxy clusters are the domain of early-type galaxies, while galaxy groups and the looser environment along cosmic filaments are the domains of spiral galaxies. The wider surroundings of galaxy clusters are a prime target for studying these transformation processes. A survey of the morphology of the neutral hydrogen around galaxies in the vicinity of galaxy clusters (and in the field) would enable us to make a tremendous advancement in the understanding of the processing of gas in galaxies. Neutral hydrogen is the cool phase of the most abundant atom in the universe and is observable in the 21 cm radio line with radio telescopes like MeerKAT.
MeerKAT has carried out exactly such a survey—the MeerKAT Galaxy Cluster Legacy Survey (MGCLS; Knowles et al. 2022)—dedicating approximately 1 200 hours of observing time to around 150 galaxy clusters. Therefore, this project exploits available data from the MeerKAT radio facility in South Africa. Several cluster fields at z<0.1 have been processed and contain neutral hydrogen data. Thanks to MeerKAT’s field of view and frequency coverage, the survey spans a broad range of environmental densities. While the velocity resolution of 44 km/s limits precise measurements of individual galaxy velocity structures, the survey’s depth enables the detection of tenuous neutral hydrogen as galaxies interact with their surroundings.
In this project, the student will analyse the properties of gas in galaxies as they are observed progressively closer to galaxy clusters. They will characterise galaxy morphologies to identify the processes responsible for gas loss and, potentially, gas accretion. A key aspect of this work involves the automated detection and analysis of neutral hydrogen data, with the potential use of machine-learning techniques to identify interacting HI disks. Additionally, the student will apply various analysis methods to determine the mass, size, and orientation of the gas, including identifying the characteristic radius and cluster properties where the transition between galaxy types typically occurs within a given environmental density.
Supervisors: Prof Oleg Smirnov (osmirnov@gmail.com)
Prof Aaron Golden (University of Galway, aaron.golden@universityofgalway.ie)
The most recent Gaia data release (DR3) has surveyed over 1.8 billion stellar sources, with parallax estimates for ~80%. Using the astrophysical parameters available from spectrophotometric information derived from these observations combined with machine learning, over 12 million sources have been classified into 22 variability types in the Milky Way and LMCs. Of particular interest is being able to confirm variability class association at other passbands, particularly the nonthermal emission properties associated with such stellar variability detectable in the GHz regime. This project will combine transient survey analysis using MeerKAT and rigorous statistical cross-correlation with Gaia's transient archive to match predicted class variables, in particular RS CVn systems, and provide targets for follow up definitive confirmation using high R spectroscopy using SALT. Each class of transient will be studied in the context of radio detection/non-detection against other multiwavelength data. See full project description.
Supervisors: Prof Gianni Bernardi (giannibernardi75@gmail.com)
Prof Oleg Smirnov (osmirnov@gmail.com)
The Hydrogen Epoch of Reionization Array (HERA) is currently in an advanced stage of construction at the Karoo site, with the goal of observing the birth of the first stars and galaxies through the (still undetected) 21 cm line from the intergalactic neutral Hydrogen. The candidate will become part of the HERA collaboration, with a twofold goal: first to produce the deepest, all-sky, HERA images to date, and, second, to explore the use of closure phase quantities as an alternative method to detect the 21 cm signal. We anticipate that the candidate will develop a direction-dependent imaging algorithm for transit arrays - like HERA -, and analyze the latest HERA data release using the closure phase method. The images will allow modeling of the foreground emission - crucial to reveal the faint 21 cm signal - and the closure phase analysis is expected to significantly improve on the current limits (Keller et al., 2023). See full project description.
Supervisors: Prof Tiziana Venturi (INAF-IRA & Rhodes, tiziana.venturi@inaf.it)
Prof Oleg Smirnov (osmirnov@gmail.com)
The Abell 3528 (A3582) cluster complex is located in the Shapley Supercluster, a ~150 deg2 region in the southern sky where clusters and groups are merging and assembling at the present time, providing a unique opportunity to study the signatures and details of large scale structure formation. It is formed by the Abell clusters A3528N, A3528S, A3530 and A3532, aligned in a north-south configuration.
Previous studies in the optical, radio and X-ray bands suggest that the system is a pre-merger. As a matter of fact no trace of diffuse emission on the cluster scale, the prototypical signature of cluster mergers, has ever been detected. At the same time, the central cluster regions host brightest cluster galaxies (BCGs) exhibiting radio emission with amazing features, such as diffuse lobes and thin filaments interacting with the external medium. Moreover, several head-tail radio galaxies are present within each cluster and in the regions between them. See full project description.
Supervisors: Dr Mpati Ramatsoku (m.ramatsoku@ru.ac.za)
Dr Kenda Knowles (k.knowles@ru.ac.za)
Dr Natasha Maddox (natasha.maddox@bristol.ac.uk)
As the primary fuel for star formation, the HI content and distribution within galaxies are key measurements for understanding the evolutionary history of galaxies. This gas is dynamic, as it can be acquired, stored, consumed, expelled, and reacquired. Gas inflows support star formation and stellar mass growth, while gas removal, through internal processes like AGN feedback or external ones like tidal interactions, can quench star formation. This so-called baryon cycle is strongly affected by the environment within which galaxies reside and shapes their evolution. To understand how the gas cycle and environment are connected, we need to explore galaxies in detail and collect large samples of galaxies over a range of environments.. The combination of field of view and resolution offered by MeerKAT is critical for building statistically significant samples, offering an opportunity to address some of the open questions of what drives galaxy evolution across environments.
This project aims to conduct statistical measures of environmental effects on galaxies based on their HI and continuum properties, using the archival MeerKAT observations of 20 square degrees of the GAMA-23 field. The student will directly study the HI content and radio continuum of an ensemble of galaxies, exploring the role of the environment in building the diversity of galaxies we observe. The radio continuum will provide dust-free estimates of star formation and measurements of AGN activity of galaxies, while the spectral line data will offer measurements for the HI properties and a probe of the environment.
Supervisors: Dr Kenda Knowles (kendaknowles.astro@gmail.com)
There is currently a wealth of data being collected from SKAO precursor and pathfinder telescopes, covering a large sky area and hundreds of galaxy clusters. Diffuse cluster emission in high redshift and/or low mass clusters is expected to be faint, possibly too faint to detect on an individual basis. By using available galaxy cluster catalogues, this project aims to cross match cluster positions in the available radio data to perform stacking experiments to attempt to detect the lowest brightness extended sources within galaxy cluster environments. As a member of several radio collaborations with large volumes of radio data (MERGHERS, MALS, EMU, superMIGHTEE, LoTSS DR2) from telescopes like MeerKAT, ASKAP, LOFAR, and the uGMRT, the student will have the opportunity to work with a wide range of data and large research collaborations. Experience with Python scripting is required.
Supervisors: Dr Kenda Knowles (k.knowles@ru.ac.za)
Dr Konstantinos Kolokythas (kkolok.astro@gmail.com)
Galaxy clusters contain thousands of galaxies, which grow through the merging of galaxy groups or other clusters. These merger events set off turbulent motions and shock waves throughout the cluster volume that are uniquely imprinted in the non-thermal component of the intra-cluster medium (ICM) in the form of diffuse synchrotron radio emission. The Abell 521 cluster is characterized by a disturbed dynamic state, with multiple sub-clusters converging on its centre, exhibiting the prototype ultra-steep spectrum massive diffuse radio halo emission and two oppositely directed diffuse radio relic sources located at the cluster periphery. This project will utilise high-sensitivity MeerKAT (archival and new), and uGMRT data to generate high and low-resolution images, along with spectral index maps, to obtain a clear understanding of the origin of the non-thermal emission (radio halo and relics) in minor mergers. Through radio data analysis, image processing and spectral imaging production the student will learn radio interferometry analysis techniques and acquire essential research skills, with the findings expected to contribute to a research paper. Link to the full project description here.
Supervisors: Dr Mpati Ramatsoku (m.ramatsoku@ru.ac.za)
Prof Oleg Smirnov (osmirnov@gmail.com)
The formation and evolution of galaxies are governed by their star formation activity, with interstellar medium (ISM) playing an important role in regulating this process. The cold component of the ISM is mainly composed of fuel for star formation in the form of atomic hydrogen. It is also well established that the interaction between this gas in galaxies and the environment is a key driver of galaxy evolution. Since they are susceptible to these interactions, the panorama of gravitational and hydrodynamical physical processes in various environments can be probed using HI gas discs of galaxies. A major challenge in studying galaxy formation and evolution is understanding how these interactions manifest in HI asymmetries due to internal and external processes. However, most studies of HI asymmetry remain qualitative, relying on visual classification. While useful, visual inspection is subjective, cannot be reproduced, and complicates comparisons across different studies. Moreover, with the advent of large HI surveys generating vast amounts of data from telescopes such as MeerKAT, it is not feasible to classify each galaxy by eye.
This project aims to compare visually classified HI morphologies with quantitative morphological parameters currently in development. The goal is to eventually offer insight into establishing methods for quantifying HI asymmetries, reducing reliance on subjective visual classification in future studies.
Supervisors: Prof Ian Heywood (University of Oxford & Rhodes, ian.heywood@physics.ox.ac.uk)
Prof Oleg Smirnov (osmirnov@gmail.com)
The MIGHTEE survey aims to study the formation and evolution of galaxies across cosmic time using the MeerKAT radio telescope. It provides state of the art L-band (1.3 GHz) radio continuum imaging, which has been recently augmented by new S-band (2.5 GHz) observations in the XMM-LSS field. This project will combine these datasets to study the spectral properties of radio-detected galaxies, distinguishing between star-forming galaxies (SFGs) and active galactic nuclei (AGN). Possible research avenues include identifying radio-excess AGN, examining deviations from the far-infrared–radio correlation, constructing the S-band radio luminosity function, and identifying spectrally anomalous galaxies. This project offers the opportunity to develop a strong understanding of the techniques of observational multiwavelength astronomy, as well as extragalactic astrophysics. See full project description.
Supervisors: Prof Oleg Smirnov (osmirnov@gmail.com)
Dr Ramij Raja (ramij.raja@ru.ac.za)
Prof Tiziana Venturi (INAF-IRA & Rhodes, tiziana.venturi@inaf.it)
Galaxy clusters exhibit a wide range of astrophysical phenomena, making them prime environments for studying diffuse radio sources such as radio halos, minihalos, relics, phoenices etc. The SPT-CL J2031-4037 cluster hosts a diffuse radio source, previously classified as an intermediate-class radio halo based on poor quality Legacy GMRT and VLA data. However, recent X-ray observations have identified it as a violent merger system, comparable to the Bullet Cluster. This project will leverage high-sensitivity MeerKAT, uGMRT, and VLA data to generate high-resolution images, along with spectral index and curvature maps, allowing for a more precise classification of the source as a radio halo, minihalo, or an intermediate halo. Through radio data analysis, spectral mapping, and image processing, the student will gain essential research skills, with the potential for contributing to a student-led publication. See full project description.
Supervisors: Prof Oleg Smirnov (osmirnov@gmail.com)
Dr Ramij Raja (ramij.raja@ru.ac.za)
Prof Tiziana Venturi (INAF-IRA & Rhodes, tiziana.venturi@inaf.it)
Galaxy clusters exhibit a wide range of astrophysical phenomena, making them prime environments for studying diffuse radio sources such as radio halos, minihalos, relics, phoenices etc. The SPT-CL J2031-4037 cluster hosts a diffuse radio source, previously classified as an intermediate-class radio halo based on poor quality Legacy GMRT and VLA data. However, recent X-ray observations have identified it as a violent merger system, comparable to the Bullet Cluster. This project will leverage high-sensitivity MeerKAT, uGMRT, and VLA data to generate high-resolution images, along with spectral index and curvature maps, allowing for a more precise classification of the source as a radio halo, minihalo, or an intermediate halo. Through radio data analysis, spectral mapping, and image processing, the student will gain essential research skills, with the potential for contributing to a student-led publication. See full project description.
Supervisors: Prof Oleg Smirnov (osmirnov@gmail.com)
Dr Ramij Raja (ramij.raja@ru.ac.za)
Prof Tiziana Venturi (INAF-IRA & Rhodes, tiziana.venturi@inaf.it)
Odd Radio Circles (ORC) are intriguing radio sources, first identified in the very high sensitive wide-field images of the ASKAP-EMU survey. Since the discovery of the first ORC, few more sources have been detected in MeerKAT fields, and few others have been spotted in archival GMRT images. They are faint circles of diffuse radio emission of synchrotron origin, whose nature is still elusive. They have been associated with moderately distant elliptical galaxies, but the mechanisms leading to their origin is still to be unveiled. Given the paucity of ORC, and their unclear origin, any new finding is a valuable addition and a step towards an understanding of their nature. See full project description.
Supervisors: Prof Gianni Bernardi (INAF-IRA & Rhodes, giannibernardi75@gmail.com)
Prof Oleg Smirnov (osmirnov@gmail.com)
The Hydrogen Epoch of Reionization Array (HERA) is currently in an advanced stage of construction at the Karoo site, with the goal of observing the birth of the first stars and galaxies through the (still undetected) 21 cm line from the intergalactic neutral Hydrogen. A recent technique to detect the 21 cm signal uses the interferometric closure phase, as they are more robust to calibration errors. The analysis of HERA observations only partially confirms this hypothesis, with some limitations due to systematic effects (Thyagarajan et al., 2020; Keller et al., 2023). The candidate will explore the use of fringe rate filters to mitigate systematic effects in HERA simulated observations of the closure phase power spectrum and, if successful, will apply them to actual HERA data. See full project description.
Supervisor: Dr Stanley Kuja (s.kuja@ru.ac.za)
Designing a balanced wideband antenna operating from low frequencies for electromagnetic compatibility (EMC) metrology can be challenging. A low-cost Log-Periodic Dipole Array (LPDA) antenna with a broad frequency response and operating at very low frequencies is proposed for EMC-related measurement in a radio astronomy site. The research involves electromagnetic computational modelling of the LPDA antenna and fabrication.
With the MeerKAT+ plan of building additional 130 telescopes, the electric noise from the electronic systems such as cars, pumps, motors, etc. can be problematic and therefore needs to be tested and qualified. In addition, the electromagnetic environment of the Transient Array Radio Telescopes (TARTs) installed in South Africa and other SKA partner countries is not characterised, and the need to do so (in the near future) as TART technology advances cannot be overemphasised. TART is a collaborative project fully supported by SARAO, the University of Otago, Rhodes University, and Stellenbosch University, which is meant to build capacity for radio astronomy in Africa.
For real-time detection and characterisation of RFI on-site, a low-cost, low-power source and a wideband antenna will be required. An LPDA is a frequency-independent and multi-octave bandwidth antenna that will be good for this purpose. Its unique design allows it to maintain a relatively constant radiation pattern and impedance across a wide frequency spectrum, offering high efficiency and consistent performance. For the proposed research, a printed circuit (PC) LPDA will be designed instead of the traditional free space LPDA. The PC LPDA will be cheap to manufacture by etching the conductor pattern on a double-sided copper-clad substrate. Also, the substrate will provide a convenient, self-supporting structure. Another advantage of the PC LPDA is that the relative permittivity can be frequency dependent, and this can yield improvements in some antenna characteristics at a number of frequencies across the antenna operating band. A licensed electromagnetic simulation software is available in the physics department for the PC LPDA design and optimisation. The Electromagnetics Innovation (EMI) lab in the department is equipped with the necessary resources for the fabrication and characterisation of the LPDA prototype.
Supervisor: Dr Stanley Kuja (s.kuja@ru.ac.za)
The Transient Array Radio Telescope (TART) is an extremely low-cost, open-source 24-element radio interferometer originally developed at the University of Otago. As a live, fully-featured radio telescope, TART provides an exceptional platform for student training in radio astronomy and RF design prototyping. This project will focus on the design aspects for upgrading the current version of TART to improve its performance. Link to full project description here. This project has dedicated funding through the Rhodes University/SARAO Group Grant.