Quark-Novae Ia in the Hubble diagram: implications for dark energy

The accelerated expansion of the Universe was proposed through the use of Type-Ia supernovae(SNe)as standard candles.The standardization depends on an empirical correlation between the stretch/color and peak luminosity of the light curves.The use of Type-Ia SNe as standard candles rests on the assumption that their properties(and this correlation)do not vary with redshift.We consider the possibility that the majority of Type-Ia SNe are in fact caused by a Quark-Nova detonation in a tight neutron-star-CO-white-dwarf binary system,which forms a Quark-Nova Ia(QN-Ia).The spin-down energy injected by the Quark-Nova remnant(the quark star)contributes to the post-peak light curve and neatly explains the observed correlation between peak luminosity and light curve shape.We demonstrate that the parameters describing QN-Ia are NOT constant in redshift.Simulated QN-Ia light curves provide a test of the stretch/color correlation by comparing the true distance modulus with that determined using SN light curve fitters.We determine a correction between the true and fitted distance moduli,which when applied to Type-Ia SNe in the Hubble diagram recovers the?M=1 cosmology.We conclude that Type-Ia SNe observations do not necessitate the need for an accelerating expansion of the Universe(if the observed SNe Ia are dominated by QNe Ia)and by association the need for dark energy.