A distance-independent calibration of the luminosity of type Ia supernovae and the hubble constant

We present a calibration of the absolute magnitude of Type Ia supernovae (SNe Ia) at maximum by means of radioactive decay models for the light curve. Comparison of the calculated late time thermalized radiation with a bolometric light curve constructed from observations circumvents problems of modeling the complex physics that govern the peak phase and avoids the conversion of theoretical luminosities into filter magnitudes. The parameter space for the absolute magnitude is explored with several explosion models and a range of rise times. The absolute B magnitudes at maximum are then used to derive a range for the Hubble constant and the distance to the Virgo Cluster of galaxies from SNe Ia. Critical examination of the Hubble diagram of SNe Ia at peak yields rigorous limits for H₀ of 45 and 105 km s^-1 Mpc^-1. Surprisingly, our determination of the value of H₀ is limited strongly by the unknown extinction toward individual supernovae. Improvements on the values of the Hubble constant from SNe Ia remain mainly in spectral modeling to find appropriate explosion models and in the use of near-infrared filters which are affected less by extinction.