Influence of Type Ia Supernova Environment and Their Peculiar Velocities on Distance measurements
2019 February 01
Type Ia Supernovae (SNe Ia) are widely used to measure the expansion of the Universe. To perform such measurements the luminosity and cosmological redshift of the SNe Ia have to be determined. The luminosity can be measured thanks to so-called standardization procedure that allows to correlate a luminosity of a supernova with its light curve or spectrum parameters. Unfortunately, even after the standardization procedures there is a remaining dispersion on the Hubble diagram. This dispersion can be due to environmental effects (age, chemical composition, dust around a SN) which are not yet taken into account. Besides the standardization of SN Ia, the Hubble diagram contains another parameter, i.e. the supernova cosmological redshift. In fact the redshift observed on the Earth is also affected by peculiar velocities. The exact contribution of peculiar velocities in the observed redshift is unknown, however it was shown that the peculiar velocities have an impact on the distance measurements and therefore can potentially affect the cosmological analysis. Here, we discuss the impact of SN environment and peculiar velocities on the distance measurements and cosmology. In the epoch of large transient surveys, development of observational techniques and further processing of the data, a study of any possible sources of systematical uncertainties in the cosmological analysis is of high priority.