Sthabile Kolwa, PhD

The University of Johannesburg

Hello! I am Sthabile - a lecturer at the Physics Department of the University of Johannesburg. I am also a postdoc at IDIA, Cape Town.

Past and current research topics of interest include:
The circumgalactic medium:
  • The structure and origin of multi-phase halo gas surrounding radio galaxies
  • Observational constraints on AGN feedback
Radio-selected AGN and their host galaxies:
  • Radio AGN and their environments
  • The AGN and host galaxy connection
Radio source characterisation
  • Quantifying sources of bias and selection effects in radio continuum surveys
  • The properties of radio-selected star-forming galaxies and AGN hosts


Radio source characterisation
... MeerKAT L-band and uGMRT (upgraded Giant Metrewave Radio Telescope) band-3 and band-4 observations are combined to obtain spectral indices of star-forming and radio galaxies up to z=5. The spectral indices are indicative of the physical mechanisms that power radio emission within these galaxies (Kolwa et al in prep.).
The multi-phase circumgalactic medium
... HeII 1640Å emission lines detected with the VLT/MUSE trace the warm-hot ionised gas (T~10,000 K) within the extended halo of a z=2.92. The extracted spectral lines are thermally broadened by photoionising radiation from the AGN (Kolwa et al. 2019b).
... Left: A spectral fit to the NV 1240Å line reveals the velocities of absorbers associated with the extended emission line gas. Right: CLOUDY photoionisation grid models for the abundances are compared to the observed constraints on column densities of CIV and NV (Kolwa et al 2019b).
Group environments of Active Galactic Nuclei
... The environment overdensity measure shown as a function of 1.4 GHz radio luminosity for VLA-detected AGN in the SDSS Stripe 82 field (Kolwa et al. 2019a).
Publications Lists



The University of Johannesburg (UJ)

In this position, I teach an electrodynamics course to second-year engineering students and a course on astrophysical radiative processes for fourth-year physics majors.

Additionally, my postdoc research with the MeerKAT/MIGHTEE working group continues and I maintain an institutional affiliation with IDIA.

January 2021 - present

Postdoctoral Research Fellow

The Inter-University Institute for Data Intensive Astronomy (IDIA)

As a postdoc, I begun research that makes primary use of MeerKAT and uGMRT radio continuum data (in addition to multiwavelength ancillary data) to study galaxy evolution.

January 2020 - December 2020

Doctoral Student

The European Southern Observatory (ESO)

As a PhD student, I completed a thesis on the circumgalactic medium of radio AGN host galaxies which made primary use of VLT/MUSE and ALMA data.

August 2016 - December 2019

Click here for the rest of my academic CV.


Ludwig-Maximilians-Universität München


2016 - 2019

The University of the Western Cape


2014 - 2015

The University of Cape Town


2010 - 2013


I maintain an involvement in community projects and initiatives that encourage the young to develop their potential and build skills that will possibly lead them to pursue STEM careers. I do this as a member of the Astronomy in Colour collective.


I am an avid reader of non-fiction and also revel in writing my own content which you can find on Medium. Here, you can peruse a couple articles I have written on recent discoveries in Astronomy and my adventures with Python.

Over the last couple years, I have casually picked up acoustic guitar which I play for relaxation and self-expression. I enjoying singing from time to time too. I'm privileged to live in South Africa - a country with many gorgeous landscapes - where I am spoilt for choice of outdoor places to escape to.


Awards & Funding Grants

  • Research grant recepient in the NRF (National Research Foundation) BAAP (Black Academic Advancement Program) (2023)
  • ESO Ph.D. Studentship (2016 - 2019)
  • Admission to the International Max Planck Research School (IMPRS), Astrophysics Ph.D. Class of 2016 - 2019
  • Scholarship recipient in the NRF-SKA (Square Kilometer Array) BSc and MSc Bursary Program (2011 - 2015)