Login

Extraplanar gas in galaxies:
To understand how galaxies acquire and recycle gas, I study the interaction between galactic disks and the surrounding circumgalactic medium. In edge-on and moderately inclined systems, deep HI observations allow the thin rotating disk to be separated from gas located above and below the plane, commonly referred to as extraplanar HI, which often shows kinematics that deviate from simple disk rotation. Ultra-deep MeerKAT observations from the MHONGOOSE survey, combining high spatial resolution with exceptional column-density sensitivity, enable detailed mapping of thick HI disks and extended gaseous halos reaching several kiloparsecs above the galactic plane. Detailed tilted ring modelling is then used to characterize these structures and constrain their origin, distinguishing contributions from internal feedback, external accretion, or a combination of both.

Galaxies in low density environments
Voids are the most underdense regions of the cosmic web, and galaxies that reside in them tend to assemble later and often retain signatures of early evolutionary processes. Numerical simulations further suggest that voids are not completely empty, but contain faint internal substructure, including tenuous filaments that may act as channels for cold gas accretion onto galaxies. The Local Void, the nearest large void, is therefore a valuable system for such studies. However, a significant fraction of this region lies behind the Galactic plane of the Milky Way, where dust obscuration and stellar crowding have historically limited optical studies, leaving the Void poorly explored. Using data from the SARAO MeerKAT Galactic Plane Survey (SMGPS), I led the first blind, wide-area interferometric HI survey of this obscured region, comprising 440 MeerKAT pointings and covering 150 square degrees, mapping the three-dimensional distribution of galaxies across the Local Void and its boundaries. This work established the Void’s extent and revealed filamentary substructure embedded within and around the Void, providing direct observational insights into galaxy growth in extremely low-density environments. I also study extremely metal-poor dwarf galaxies located in nearby voids using MeerKAT and uGMRT HI observations. Despite their apparent isolation, these systems have shown disturbed HI morphologies and misaligned gas and stellar components, indicating dynamically unsettled gas. These signatures may point to ongoing cold-gas accretion along faint filaments. We are currently expanding this work with additional MeerKAT and uGMRT observations to build statistically larger samples and to better understand galaxy evolution in near-pristine environments.

Kinematics and dynamics of galaxies
A central part of my research concerns how galaxies acquire and redistribute angular momentum. Using HI kinematics across systems spanning ultra-diffuse galaxies, dwarf galaxies, and massive spirals, I established that the gas specific angular momentum-mass relation follows a single, continuous power law over several orders of magnitude in mass. Early-type galaxies that show clear signatures of recent gas accretion are the main exceptions, and they exhibit elevated gas angular momentum. Over the last decade, global scaling relations between specific angular momentum and mass have been established separately for stars, gas, and baryons, with each component following a distinct trend and slope. However, global relations average over entire galaxies and do not show how angular momentum is distributed internally or how structural differences between components shape these relations. I am now extending this work using ultra-deep MeerKAT observations from the MHONGOOSE survey to examine how angular momentum builds up in a spatially resolved sense and how gas, stars, and total baryons contribute to mass and specific angular momentum as a function of radius, while also identifying galaxies with internal angular momentum disturbances associated with recent gas accretion, interactions, or feedback. Another aspect of my research has involved the dark matter distribution in galaxies. ΛCDM models predict cuspy inner density profiles, whereas dwarf galaxy observations often indicate shallower cores. This discrepancy, known as the cusp–core problem, is partly linked to systematic effects in rotation curve modelling. We derived dark matter density profiles for dwarf galaxies in void environments using rotation curves obtained from both traditional two dimensional tilted ring analysis and full three dimensional modelling of the data cube, and found that the inferred inner density slope depends on the modelling approach. We also compared the resulting halo parameters with those of similar galaxies in average-density environments and examined superthin galaxies, where compact dark-matter halos appear connected to the stability of extremely thin stellar disks.