Stellar Populations in type Ia supernova host galaxies at intermediate-high redshift: Star formation and metallicity enrichment histories

We present a summary of our project that studies galaxies hosting type Ia supernova (SN Ia) at different redshifts. We present Gran Telescopio de Canarias (GTC) optical spectroscopy of six SN Ia host galaxies at redshift z similar to 0.4-0.5. They are joined to a set of SN Ia host galaxies at intermediate-high redshift, which include galaxies from surveys SDSS and COSMOS. The final sample, after a selection of galaxy spectra in terms of signal-to-noise and other characteristics, consists of 680 galaxies with redshift in the range 0.04 < z < 1. We perform an inverse stellar population synthesis with the code fado to estimate the star formation and enrichment histories of this set of galaxies, simultaneously obtaining their mean stellar age and metallicity and stellar mass. After analysing the correlations among these characteristics, we look for possible dependencies of the Hubble diagram residuals and supernova features (luminosity, colour and strength parameter) on these stellar parameters. We find that the Hubble residuals show a clear dependence on the stellar metallicity weighted by mass with a slope of -0.061 mag dex(-1), when represented in logarithmic scale, log < Z(M)/Z(circle dot)& rang;. This result supports our previous findings obtained from gas oxygen abundances for local and SDSS-survey galaxies. Comparing with other works from the literature that also use the stellar metallicity, we find a similar value, but with more precision and a better significance (2.08 versus similar to 1.1), due to the higher number of objects and wider range of redshift of our sample.

Automated summary

In this study, we investigate galaxies hosting type Ia supernova (SN Ia) at different redshifts, using Gran Telescopio de Canarias (GTC) optical spectroscopy and inverse stellar population synthesis. We estimate the star formation and enrichment histories of these galaxies and find a clear correlation between the Hubble residuals and stellar metallicity. These results are important for understanding galaxy evolution and the mechanisms behind SN Ia explosions.