Direction Dependence in Supernova Data: Constraining Isotropy

Understand

We revise and extend the extreme value statistic, introduced in \cite{gup08}, to study directional dependence in the high redshift supernova data; arising either from departures from the cosmological principle or due to direction dependent statistical systematics in e data.

• We introduce a likelihood function that analytically marginalises over the Hubble constant, and use it to extend our previous statistic.
• We also introduce a new statistic that is sensitive to direction dependence arising from living off-centre inside a large void, as well as previously mentioned reasons for anisotropy.
• We show that for large data sets this statistic has a limiting form that can be computed analytically.