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Identifier 000446585
Title A multi-wavelength study of extragalactic supernova remnants
Alternative Title Μελέτη εξωγαλαξιακών υπολειμμάτων υπερκαινοφανών σε πολλαπλά μήκη κύματος
Author Κοψαχείλη, Μαρία Β.
Thesis advisor Ζέζας, Ανδρέας
Reviewer Παπαδάκης, Ιωσήφ
Παυλίδου, Βασιλική
Χαρμανδάρης, Βασίλης
Reig, Pablo
Μπούμης, Παναγιώτης
Χατζηδημητρίου Δέσποινα
Abstract Supernova Remnants (SNRs) play an important role in the feedback and the shaping of the interstellar medium (ISM) and consequently of the entire galaxy. In this thesis, we aim to provide new tools, which allow the study of different SNR populations, as well as, the comparison between different studies and models. We also present new candidate SNRs in nearby galaxies. We construct new diagnostics for the optical identification of SNRs which are more efficient in low excitation SNRs, unlike the commonly used [S II] (λλ6717,6731 ÅÅ)/Hα diagnostic. These new diagnostics combine emission-line ratios of strong forbidden lines, in 1, 2 and 3 dimensions and they can increase the number of the identified SNRs up to ~35%, compared to the [S II]/Hα diagnostic. In addition, we identify SNRs in the galaxies NGC45, NGC55, NGC1313, and NGC7793 following a totally automated method. We present 97 candidate SNRs (84 of which, are new identifications). The automated approach for the SNR identification, allows us to calculate the incompleteness and construct the Hα and the joint Hα-[S II] luminosity functions, free of selection effects. We also introduce the excitation function and we find that there is a trend for more luminous SNRs to exhibit lower excitation. This is probably due to the fact that the more luminous SNRs are in regions with increased Hα background, or embedded in H II regions. Motivated by the lack of theoretical models for the luminosity distribution of SNR populations, we develop a formalism for the construction of theoretical luminosity functions. These are based on shock models that predict the emerging emission-line luminosity of shocks for a wide range of ISM parameters, coupled with the velocity of shocks in the Sedov-Taylor phase. This way, we construct theoretical Hα and the joint (Hα- [S II]) luminosity functions. The comparison between theoretical and observational luminosity functions, shows very good agreement.
Language English
Subject Hii regions
Luminosity functions
NGC 1313
NGC 45
NGC 55
NGC 7793
Shock models
Περιοχές ιονισμένου υδρογόνου
Σοκ μοντέλα
Συναρτήσεις λαμπρότητας
Υπολείμματα υπερκαινοφανών
Issue date 2022-05-09
Collection   School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses
  Type of Work--Doctoral theses
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