Modisha Tladi


Email: tladi.modisha at

Supervisor: Dr Ed Elson, Co-supervisor: Prof. Roy Maartens

Research topic: Mock HI spectral line stacking experiments for large galaxy surveys.

My work focuses on carrying out neutral atomic hydrogen (HI) stacking experiments on existing and new HI data products in order to quantify the typical amounts of additional flux in these experiments. The amounts of additional flux that we explore are due to source confusion (the effect that occurs when the extracted target galaxy spectrum is contaminated by flux from nearby neighbouring galaxies) and point spread function (PSF) contamination (the effect that arises due to the manner in which a PSF with large side lobes and spatially extended features can redistribute the flux of a point source throughout the entire spatial domain of a cube). Our newly-generated data products were produced using simulation methods on the Common Astronomy Software Applications (CASA) software to incorporate the effects of realistic PSFs -which introduces more realism. We also produced data products that were free from the effects of PSFs – which were representative of the perfect case. We then implemented a stacking software and applied it on the perfect and realistic data products to explore the uncertainties in the results from HI stacking experiments due to the inclusion of additional flux from source confusion and PSF contamination components, respectively.