Mason Ng

Investigated the effects of different magnetic field strengths and configurations on the structure of the stellar atmosphere of solar-type stars.

Studied absorber kinematics of 31 OVI absorbers, which exhibited a strong halo mass dependence, where absorbers hosted by L* galaxies have the largest velocity dispersions compared with lower masses and group environments, due to a match between virial temperature and the temperature at which OVI ionization fraction is greatest. Total column densities follow the same behavior, consistent with simulations. Relative absorber--galaxy kinematics of the same sample was studied, though the mass dependence was first normalized out to account for the range of halo masses in the sample. Non-virialized motions due to outflowing gas was observed. Accreting gas signatures were not observed due to multiple line-of-sight structures that were observed, resulting in "kinematic blurring". These results indicate that OVI is not an accurate probe of baryon cycle processes.

There were two projects I carried out:

1) I performed evidence calculations with a trio of codes (CosmoMC, PolyChord, and ModeCode) on several inflationary models, most notable of which is the inflection point inflationary model. Results obtained showed that it is comparable in likelihood to quadratic potentials.

2) I also looked at quantifying the impacts of dark matter on the cosmic microwave background using the 2015 Planck likelihoods, in order to demonstrate the predictive power of dark matter. It was found that dark matter was needed at least at the $10^{100}$ level. While the physical effects of dark matter are well-understood, this quantitative calculation has not been reported in the literature.owave Background.

The results are all summarized in my Senior thesis (US)/Honours thesis (NZ/Aus).

The project involved training a computer to predict image quality from the SkyMapper telescope by considering environmental conditions and telescope configurations. The SkyMapper telescope atop Siding Spring Observatory surveys the entire Southern sky in multiple wavelengths. SkyMapper will inevitably find millions of celestial objects. One result was that the angle of rotation of the CCD camera resulted in visibly lower quality images. Once this was discovered, the SkyMapper team disabled that telescope setting.

Working with Georgie Taylor, we created over 1300 stellar atmosphere models for use in BPASS, the state-of-the-art code incorporating binary stellar systems to predict properties of stellar populations. Results of our work have contributed to the analysis of the recently announced gravitational waves, where it was concluded that similar events are more likely to occur in low-metallicity environments.