Search

The accuracy needed to identify the nature of dark energy in the Universe is one order of magnitude smaller than the present scatter in the observed local relation used to calibrate Type Ia SNe as standard candles. In order to reduce this scatter and to identify potential evolutionary effects, we have studied the influence of the physical and chemical properties of progenitors on SNe Ia light curves. First, we considered the mass and composition of WD progenitors and then we took into account rotation during the WD accretion phase, obtaining super-Chandrasekhar mass WDs. Differences in the maximum magnitude are of the same order as the present scatter in the calibration relation. In the context of the one dimensional delayed detonation model we assume the same transition density in all our models, implying that similar amounts of radioactive nickel are synthesized and, thus, similar magnitudes at the maximum epoch of the light curve are obtained. To establish, from a theoretical point of view, the required links between progenitors and outcomes, we have to fully understand the physics of Type Ia SNe, otherwise we may have already reached their limit as a probe of the structure of the Universe. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

High redshift SNe Ia have been recently used to calibrate the cosmological distance scale and to infer the existence of the dark energy. The reliability of such a method depends on the effective knowledge of the absolute brightness of this class of supernovae. This would require a complete understanding of the physics of SNeIa. Starting from an accreting rotating white dwarf, the only progenitor that we found to be able to grow till the Chandrasekhar mass and undergo a thermonuclear explosion, we simulate the explosion, deriving the nucleosynthesis and the light curve. We explore the final outcome in the framework of a 1D delayed detonation model, where the characteristic density for which the transition from deflagration to detonation takes place is a free parameter. Although preliminary, our results imply that rotating white dwarfs produce a range of explosive conditions, characterized by different ignition densities and total masses. Maximum luminosities of successfully explosive models differ up to 0.11 mag. In a few cases, the formation of a small highly neutronised remnant is found. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]