First off, here is a link to my publication list, hosted as a Nasa ADS Library page
. The short version of this page is that my interests in astronomy are rather varied, and have covered a lot of ground over the years. Currently, I'm mainly interested in multiwavelength observations of Galactic transients, especially classical novae. This is where I'm anticipating the majority of my future (and current) research to be focused. As a Ph.D. student, my research focused on measuring the gravitational potential of the Milky Way using various novel dynamical methods. But we also were working on surveys to use strong lensing of supernovae to measure the Hubble constant through time-delay cosmography, and on two other projects aimed at studying Galactic structure. You can find some brief descriptions of various projects that I've led (or been heavily invovled with) below on this page, sorted by topic. The classical nova section describes my current research focuses, while other sections are completed projects from my Ph.D. work. If you'd like any more information, there are links to all the relevant papers here, and also feel free to send me an email if you'd like to know more!
My work in classical novae focuses on using multi-wavelength observations of a large sample of Galactic novae. The goal is to improve our understanding of the underlying physics, especially related to mass ejection mechanisms and internal shocks in the ejecta. Along the way, we've been revisiting some classic nova papers with more modern data sets. Check out one of my nova papers on the optical colours of classical novae , that revisits a paper from 1987 studying the (B-V) colours of novae. In 1987, a sample of ~7 novae was possible that had photometry in consistent filters. Now we have almost 70, although only about 25 of those have the reliable reddening estimates needed to measure the colours. Novae tend to be fairly individualistic, but it turns out that their photometric colours at peak are fairly consistent (and even more so after the light curve has declined by 2 magnitudes). This is useful for providing an easy mechanism to measure the reddening towards novae.
An undergraduate working in our group us has recently released a nice paper studying the dust-forming characteristics of novae, which can be found here . This is a nice result showing that 50-70% of novae show evidence for the formation of dust in their light curves, which is a significantly higher fraction than previously estimated. Included in this work is a method that can be used to identify dust-forming novae with fairly limited information in the optical and near-IR.
I've been working recently on a paper studying what drives the γ-ray emission in novae. This is a work in progress, but we expect to have a paper released sometime in the first half of 2025. One of the aims of this paper is to test the predicted relationships between the optical properties of novae, such as the outflow expansion velocity, and the γ-ray luminosities. Potentially, this can enable constraints on the underlying physics of the shocks that are thought to be responsible for the production of γ-rays in novae, and confirm the origin of these internal shocks. Keep an eye out for this if you are interested, and a link will get posted here when it is available.
Most of my Ph.D. research was focused on Galactic dynamics, with a particular interest in measuring the potential of the Milky Way (MW). Our aim was generally to find novel approaches to measuring the potential, usually trying to use new forms of information that haven't been adapted for this previously. These checks often entail some caveats and uncertainties, but have the benefit of being independent of typical measurement techniques. In some cases, these methodologies have considerable potential for improving our Galactic mass estimates in the future, as new data sets become available.
One project to do this used hydrodynamical simulations of the Magellanic Stream (MS), the formation of which is sensitive to the assumed Galactic potential. Varying the assumed potential properties in our simulations produces different properties of the derived stream, especially the length. After producing a series of simulations with different masses for the MW, a straightforward linear relationship appears between the MW mass and the length of the simulated stream. Based on real observations of the stream, we can estimate the true stream length, and use that as an estimator of the MW mass. While there remains considerable uncertainty in the result here, it is a novel method that produces a very reasonable estimate for the MW mass, consistent with several other mass estimators. A video of one of these simulations is shown below, displaying the two Magellanic clouds falling into the gravitational potential of the MW, and interacting with diffuse gas surrounding the MW.
If you're interested in more details, feel free to check out the paper here.
I've also been invovled in a survey, called LCOLSS, attempting to identify supernovae in strongly lensed galaxies. The goal was ultimately to provide a measurement of the Hubble constant that is independent of the distance ladder typically required when using Type Ia supernovae. While we unfortunately did not manage to find any good sources, we can constrain the detection rates to be expected from future targeted surveys searching for similar targers.