Supernova light-curve fitters and Dark Energy

TL;DR

This paper investigates how different supernova light-curve fitters can cause apparent tensions in cosmological data sets and influence the preference for dark energy models, highlighting the importance of fitter choice.

Contribution

It reveals that the choice of light-curve fitter can create or mask tensions between supernova data and other cosmological observations, affecting model selection.

Findings

Different fitters can produce distinct supernova data sets.

Fitter choice impacts the inferred preference for phantom dark energy models.

Tensions between data sets may originate from fitter inconsistencies.

Abstract

We show that when a procedure is made to remove the tension between a supernova Ia (SN Ia) data set and observations from BAO and CMB, there might be the case where the same SN Ia set built with two different light-curve fitters behaves as two separate and distinct supernova sets, and the tension found by some authors between supernova sets actually could be due to tension or inconsistency between fitters. We also show that the information of the fitter used in an SN Ia data set could be relevant to determine whether phantom type models are favored or not when such a set is combined with the BAO/CMB joint parameter.