Doctoral theses
Current Record: 14 of 171
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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
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Κοψαχείλη, Μαρία Β.
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Thesis advisor
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Ζέζας, Ανδρέας
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Reviewer
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Παπαδάκης, Ιωσήφ
Παυλίδου, Βασιλική
Χαρμανδάρης, Βασίλης
Reig, Pablo
Μπούμης, Παναγιώτης
Χατζηδημητρίου Δέσποινα
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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.
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Language |
English |
Subject |
Hii regions |
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Luminosity functions |
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NGC 1313 |
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NGC 45 |
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NGC 55 |
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NGC 7793 |
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Shock models |
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Περιοχές ιονισμένου υδρογόνου |
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Σοκ μοντέλα |
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Συναρτήσεις λαμπρότητας |
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Υπολείμματα υπερκαινοφανών |
Issue date |
2022-05-09 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses
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Type of Work--Doctoral theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/2/9/3/metadata-dlib-1647252211-97547-9977.tkl
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Views |
665 |