Metallicity Estimation of Core-Collapse Supernova Environments within 30 Mpc

This thesis researches the local metallicities of environments of Type IIP, Type Ib and Type Ic supernovae (SNe), within a luminosity distance of 30 Mpc, by long-slit spectroscopy. During the runtime of the project 76 targets out of a sample of 110 selected targets could be observed at the Isaac Newton Telescope (INT) on La Palma. For 66 observed targets the metallicities could be measured by the N2 and O3N2 strong emission line methods, using calibrations of Pettini and Pagel (2004, PP04) and Marino et al. (2013, M13). The PP04 mean values of the local metallicities are about 8.62 dex. The metallicities by M13 are about 0.1 dex less. No significant differences between the means of the three SN types have been found. The sample of the INT observations has been extended by the results of previous work of 46 targets meeting the selection criteria of the project. Again, no significant differences between the means of the three SN types have been found. Normalised cumulative distribution functions (CDFs) of the metallicities of the three SN types are presented. Type Ib and Ic distributions tend to higher metallicity than Type IIP, however Type Ic SNe are also present at lower metallicities whereas Type Ib SNe are not. The Type Ib distribution is narrower than both the Ic and IIP distributions. The Kolmogorov-Smirnov test as well as the Anderson-Darling test indicates no statistical significance for a difference in the local metallicities of the three SN types. The narrow CDFs of Type Ib SNe give some evidence for a significant fraction of single massive progenitor stars, whilst the low metallicity of Type Ic suggests a significant fraction of compact binary progenitors. More observational data and additional statistical tests such as Monte Carlo simulation by future work are required to further constrain the progenitor stars of Type Ib,c SNe

Metallicity Estimation of Core-Collapse Supernova HII Regions in Galaxies within 30 Mpc

This work presents measurements of the local HII environment metallicities of corecollapse supernovae (SNe) within a luminosity distance of 30 Mpc. 76 targets were observed at the Isaac Newton Telescope and environment metallicities could be measured for 65 targets using the N2 and O3N2 strong emission line method. The cumulative distribution functions (CDFs) of the environment metallicities of Type Ib and Ic SNe tend to higher metallicity than Type IIP, however Type Ic are also present at lower metallicities whereas Type Ib are not. The Type Ib frequency distribution is narrower (standard deviation ∼0.06 dex) than the Ic and IIP distributions (∼0.15 dex) giving some evidence for a significant fraction of single massive progenitor stars; the low metallicity of Type Ic suggests a significant fraction of compact binary progenitors. However, both the Kolmogorov-Smirnov test and the Anderson-Darling test indicate no statistical significance for a difference in the local metallicities of the three SN types. Monte-Carlo simulations reveal a strong sensitivity of these tests to the uncertainties of the derived metallicities. Given the uncertainties of the strong emission methods, the applicability of the tests seems limited. We extended our analysis with the data of the Type Ib/Ic/IIP SN sample from Galbany et al. (2018). The CDFs created with their sample confirm our CDFs very well. The statistical tests, combining our sample and the Galbany et al. (2018) sample, indicate a significant difference between Type Ib and Type IIP with <5% probability that they are drawn from the same parent population