On the influence of the host galaxy in supernova cosmology

In cosmology, we use Type Ia Supernovae (SNe Ia) along with other probes, to study the evolution of our universe. In this thesis, I have shown that the host galaxies of SNe Ia can change their luminosities, which can bias cosmological results. I have also shown how to obtain better standard candles by studying SNe Ia in different host galaxy types. My work is important for the current and future supernova surveys in reducing astrophysical systematic in supernova cosmology.