Non-parametirc reconstruction of expansion history of the Universe
Arman Shafieloo1,2, Tim Clifton3, Pedro Ferreira3
1Theoretical Physics, University of Oxford, Oxford, Oxfordshire, United Kingdom; 2Institute for the Early Universe, Ewha Womans University, Seoul, Republic of Korea; 3Astrophysics, University of Oxford, Oxford, Oxfordshire, United Kingdom

We propose a new statistic that has been designed to be used in situations where the intrinsic dispersion of a data set is not well known: 'The Crossing Statistic'. This statistic is in general less sensitive than “χ2” to the intrinsic dispersion of the data, and hence allows us to make progress in distinguishing between different models using goodness of fit to the data even when the errors involved are poorly understood. The proposed statistic makes use of the shape and trends of a model's predictions in a quantifiable manner. It is applicable to a variety of circumstances, although we consider it to be especially well suited to the task of distinguishing between different cosmological models using type Ia supernovae. We show that this statistic can easily distinguish between different models in cases where the “χ2” statistic fails. We also show that the last mode of Crossing Statistic is identical to “χ2”, so that one can consider it as a generalization of “χ2”.

Keywords: Likelihood; Non parametric statistical method; Parameter estimation; Supernovae data

Biography: I am a cosmologist working on different statistical methods of data analysis to reconstruct the cosmological quantities and parameters of the universe in a relatively model-independent way.