Research Interests

Why astronomy?

After completing a B. Math/B Science at the University of Newcastle and spending two years in the Australian Air Force, I began honours in Physics at the University of Sydney mid-2001. A project in astronomy struck me as most interesting because of the sheer bredth of the field. The Universe is a big place where many different kinds of existing and new physics can be applied, and the techniques used by astronomers push the limits of other fields, e.g. imaging algorithms and low-noise detectors.

Honours Work

My honours project consisted of analysing data from the aperture-masking experiement MAPPIT which was based at the Anglo-Australia Telescope, with a little astronomical interpretation. My complete honours thesis in gzipped .ps format can be found here. The unique part of this work was the use of the wavelength-dispersed fringes from the experiment to solve for atmospherically-induced delays over the sub-apertures in the experiment. This in turn meant that data in strong TiO absorption bands could be coherently integrated. See my honours thesis or the more brief MNRAS paper for more details.

Work During my PhD

As of October 2004, my PhD thesis doesn't yet have a title. This is due to the broad range of subtopics within astronomical optical interferometry that I've been interested in and worked on. I'll need a title before July 31 2005, my official submission date. I guess the three main areas of work have been:

1. Technical development at SUSI: I've contributed to optical design changes at SUSI, as well as the the software, astronomical Comissioning and some hardware involved in the new CCD-based tip/tilt adaptive optics system, fringe scanning and data acquisition systems. I've also written the SUSI data analysis pipeline. Other fun and interesting work that won't end up in the PhD has been bugshooting a range of existing systems, porting old software to RT-linux and creating a scheduler to ease the pressure on the observer. In principle, SUSI runs itself once internally aligned (in practice there are several tweaks best done by a real observer). The unique challenges here have been in overcoming the very low signal levels for tip/tilt and automatic fringe acquisition and tracking.

2. Aperture masking interferometry: This was originally a back-up plan due to uncertainty in funding for the SUSI project, however I've remained somewhat involved in projects initiated by my supervisor and other collaborators. I have my own pipeline for data analysis from a range of aperture masking experiments including imaging code. I hope to publish some results that require data analysis techniques unique to my new code before completing my PhD (I realise not many people will actually read my thesis).

3. Modelling the atmospheres of Mira variables: This work started off being driven by Michael Scholz, but after he pointed me in the right direction for my repetitive question ``Just how hard can it be to model dust formation around Mira variables, I mean, really?'' curiosity has got the better of me and I'm significantly involved in the modelling process. This modelling process has three stages, a grey, time-dependent calculation done by Peter Wood in Canberra that is used to calculate pressure as a function of radius (temperature is also calculated but has significant errors in the upper layers), detailed non-grey spherical radiative transfer to solve for temperature more accurately as a function of radius, and finally predicting observable properties such as centre-to-limb variation and spectra (plus derived quantities). I've been involved in the second two stages of this processs, and have been attempting to add dust to the models. Dust is required to explain both aperture masking observations and more recent observations at SUSI, and may help in predicting fundamental stellar properties and mass-loss rates for Miras as a function of their many observable properties.