Dr Marisa Cristina March

Marisa Cristina March is currently a Postdoctral Research Fellow at the Univeristy of Sussex, and was formerly a postgraduate cosmology student at Imperial College working with Dr Roberto Trotta, in the field of dark energy science.

The somewhat surprising supernovae Ia result of the late 1990s, showing that the expansion of the universe is accelerating, brought the question of dark energy to the forefront of cosmological research. Making up some 70% of the known universe, dark energy appears to be a smooth fluid with a negative pressure, uniformly pervading the cosmos, causing an acceleration of cosmic expansion.

Although the basic characteristics of dark energy have been observed indirectly, its true nature remains unknown and a number of different dark energy models have been proposed in explanation. These rival dark energy models include, but are not limited to: the energy density of the vacuum; a modification to General Relativity and a dark energy scalar field, often termed `quintessence'.

Various cosmological probes such as supernovae Ia (standard candles) and baryon acoustic oscillations (standard rulers) can be used to probe the expansion history of the universe. By using these probes to better constrain the empirical properties of dark energy, it is possible to discriminate between the different proposed dark energy models.  

Marisa's current work focuses on applying Bayesian statistical methods to the problem of dark energy model selection, with particular reference to the use of supernovae Ia as standard candles.