Distance Determination To Eight Galaxies Using Expanding Photosphere Method

Abstract

Type IIP supernovae are recognized as independent extragalactic distance indicators, however, keeping in view of the diverse nature of their observed properties as well as the availability of good quality data, more and newer events need to be tested for their applicability as a reliable distance indicators. We use early photometric and spectroscopic data of eight type-IIP SNe to derive distances to their host galaxies using the expanding photosphere method (EPM). For five of these, EPM is applied for the first time. In this work, we improved EPM application by using SYNOW estimated velocities and by semi-deconvolving the broadband filter responses while deriving color temperatures and black-body angular radii. We find that the derived EPM distances are consistent with that derived using other redshift independent methods.