Probing ΛCDM and dark energy evolution using high-redshift type Ia supernovae
Rouk, Xander
Citations
Abstract
Distance measurements from Type Ia supernovae have been used to provide one of the most accurate measurements of the Hubble constant in the nearby universe. Recent discoveries of Type Ia supernovae by the James Webb Space Telescope (JWST) allow us to extend this measurement of the universe's expansion rate up to a redshift of 3. However, at redshifts > 2-3, when the universe is dominated by dark matter, the global properties such as cosmic metallicity and star formation rate are much different from those in the nearby universe. To study the potential evolution of dark energy, this study first focuses on the w0wa-CDM models. We fit the model parameters to the new Type Ia supernovae at redshifts greater than 1.5, which were spectroscopically confirmed by JWST. While our preliminary results remain broadly consistent with ΛCDM, minor deviations underscore possible evolutionary signatures of dark energy or the SN luminosity. In particular, since lower progenitor metallicity may boost SN Ia luminosity with redshift and dark energy parameters (such as wa) have a stronger impact on distance measurements during the dark matter-dominated era, our analysis will assess whether a larger high-redshift SN Ia sample could reveal signs of evolving dark energy rather than merely reflecting luminosity evolution of SNe Ia.