Model independent bounds on type Ia supernova absolute peak magnitude

We put constraints on the peak absolute magnitude, M₁ of type Ia supernova using the Pantheon sample for type Ia supernova observations and the cosmic chronometers data for the Hubble parameter by a model independent and nonparametric approach. Our analysis is based on the Gaussian process regression. We find percent level bounds on the peak absolute magnitude given as M₁=-19. 3840. 052. For completeness and to check the consistency of the results, we also include the baryon acoustic oscillation data and the prior of the comoving sound horizon from Planck 2018 cosmic microwave background observations. The inclusion of these two data gives tighter constraints on M₁ at the subpercent level. We obtain constraints on M₁ from the combination of Pantheon compilation of type Ia supernova observations and baryon acoustic oscillation observations given as M₁=-19. 3960. 016. When adding the cosmic chronometer observations with these observations, we find M₁=-19. 3950. 015. The mean values of peak absolute magnitude from all these data are consistent with each other and the values are approximately equal to -19. 4.