Metallicity Estimation of Core-Collapse Supernova Environments within 30 Mpc

Ganss, Rudi (2020) Metallicity Estimation of Core-Collapse Supernova Environments within 30 Mpc. Masters thesis, University of Central Lancashire.

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Abstract

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.


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