Search for Sub-classes with in Type-Ia Supernovae using Hierarchical Agglomerative Clustering (HAC)

Abstract

Search of sub-classes within Type Ia Supernovae is a topic of debate in cosmology. Researchers have considered diverse perspectives while searching for sub-classes in various studies. In the present study, SNe Ia have been investigated based on morphology of host galaxy and location of the progenitor within the host galaxy. Hierarchical Agglomerative Clustering technique has been applied on a sample of 43 type Ia Supernovae for the purpose. Our results show that spiral galaxies (Sb, Sc, Sd) favour brighter SNe Ia as compared to S0 and ellipticals. Also, the frequency of occurrence of brighter SNe is less towards the outer regions of the host galaxies. The reason could be the difference in metalicity among the host galaxies as well as the variation in metalicity at different locations within the host galaxy.