Research

PhD

Supernovae

2011fe

M101 where the Type Ia Supernova, 2011fe, occurred.

I’m currently trying to measure the volumetric supernova rate in the local universe (z<0.08). An accurate rate determination places constraints on stellar evolution models and may help in understanding supernova progenitor types. I work with data from two years of Palomar Transient Factory (PTF) observations, and detection efficiencies are calculated through the addition of fake supernovae into the PTF discovery pipeline. The fake supernovae comprehensively sample the parameter space of PTF observations and dictate the weighting for each real supernova. I will also work on an investigation into the detectability of the new class of “Calcium rich” or “faint and fast” supernovae, and place constraints on their origin.

Master’s Thesis

Blue Straggler Stars in the Globular Cluster M30

COL_BMT

The two accepted formation scenarios for BSs. Top: Stellar collisions. Bottom: Binary Mass Transfer. (Image Source)

Blue Straggler (BS) stars appear to have drunk the cosmic elixir of youth. Blue Stragglers were first observed by Allan R. Sandage in 1953 during a study of the globular cluster M3. Since then, BSs have been observed in all resolved globular clusters, but explaining thier existence has posed a challenge. All stars in globular clusters were formed at approximately the same time, with the more massive main sequence stars evolving into giant stars quicker than the less massive stars. This evolution process leaves a trace of a cluster’s age on a colour-magnitude diagram (CMD). The main-sequence turnoff (MSTO) is the position on a CMD where main sequence stars are on the cusp of evolving into red giant stars. BSs sit along an extension of the main sequence, beyond the MSTO, in a brighter and bluer region. Stars in this region should have evolved into giant stars, yet BSs remain; they seem to “straggle” and appear younger than their stellar neighbours.I investigated a claim that the position of a BS on a CMD would reveal its evolutionary history.