Relación de la luminosidad de las supernovas de tipo Ia con las abundancias elementales de sus galaxias anfitrionas

Abstract

The metallicity of the progenitor system producing a type Ia supernova (SN Ia) could play a role in its maximum luminosity, as suggested by theoretical predictions. This thesis compiles an observational analysis to study the existence of such a relationship. This work is made up of two well distinguished parts separated by the redshift: local galaxies (z < 0:02); and galaxies at intermediate redshifts (z 0:45). First, I have carried out astronomical observations using the 4.2m William Herschel Telescope (WHT) located at La Palma, where we have obtained intermediate-resolution spectroscopy data of a sample of 28 local galaxies hosting SNe Ia, for which distances have been derived using methods independent of those based on SN Ia parameters (e.g. Tully-Fisher, Cepheids). From the emission lines observed in their optical spectra, we derived the gas-phase oxygen abundance in the region where each SN Ia exploded. Our data show a trend, with an 80% of chance not being due to random fluctuation, between not reddened SNe Ia absolute magnitudes and the oxygen abundances of the host galaxies, in the sense that luminosities tend to be higher for galaxies with lower metallicities. This difference is 0:14 0:10 dex between both high and low metallicity regimes. This result seems likely to be in agreement with both the theoretically expected behavior and with other observational results. This result is extensive to reddened SNe Ia. I have performed a Principal Component Analysis (PCA) to establish the correlations between SNe Ia absolute magnitude with its light curve width and color, and with the environmental oxygen abundance. I conclude that it is possible to reduce up to 4.8% the scatter for the SNe Ia absolute magnitude if the metallicity is taken into account...