Supernovae (SNe) are massive explosions, associated with the violent deaths of certain stars. In some cases they can be used to measure cosmological distances. SNe have been observed throughout the history of mankind, and the last SN observed in our own galaxy was Kepler's SN of 1604.
Type Ia SNe are produced by the thermonuclear explosion of white dwarf stars that accrete material from a companion star, pushing them over the Chandrasekhar mass limit. These SNe are "standardizable" candles, meaning we can determine how bright they are intrinsically and measure the distance to them. Other types of supernovae are produced when massive stars reach the end of their fuel burning lives and can no longer support themselves against gravity; first collapsing and then expanding explosively. Some of the SNe produced by massive stars simultaneously produce gamma-ray bursts.
At the Dark Cosmology Centre we use observations of Type Ia Supernovae to measure cosmological distances and determine the effect of dark energy on the expansion history of the Universe. In particular, we are interested in determining how standardizable Type Ia SNe really are. We also carry out research into the nature of SN explosion mechanisms, by measuring the shapes of the explosions using polarimetry and by looking at the stars before they explode.