Browsing by Author "Ezer, Cemile."

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    Chemical enrichment history and gas mass fraction of the galaxy cluster abell 3112
    (Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2017., 2017.) Ezer, Cemile.; Ercan, E. Nihal.
    Clusters of galaxies are the largest concentrations of con ned matter in the Universe. Their deep potential well locks all metals produced by stars and galaxies within the intra-cluster medium. The spatial distribution of the metals residing in the intra-cluster medium records all the information on a cluster's nucleosynthesis and chemical enrichment history. In this work, we constrain the radial distribution of supernova enrichment via supernova type Ia and core collapse supernova explosions from a total of 1.2 Ms Suzaku XIS and 72 ks Chandra observations of the cool-core galaxy cluster Abell 3112 out its virial radius ( 1470 kpc). We adopt a recently developed snapec XSPEC model for this study. In this study, it is found that the ratio of the observed supernova type Ia explosions to the core collapse supernova explosions has a uniform distribution at a level of 0.12 { 0.16 out to the cluster's virial radius. The observed fraction of type Ia supernova explosions is in agreement with the corresponding fraction found in our Galaxy and the chemical enrichment of our Galaxy. The non-varying supernova enrichment suggests that the intra-cluster medium in cluster outskirts was enriched by metals at an early stage before the cluster itself was formed during the period of intense star formation activity. Additionally, we nd that the 2D delayed detonation model CDDT produces signi cantly worse ts to the X-ray spectra compared to simple 1D W7 models. An explicit investigation with these X-ray observations can also be used to probe the approximate baryon fraction of the cluster. In this study, the gas mass fraction is determined as fgas = 0:21+0:16 {u100000}0:11 at R500.
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    Theoretical foundations of axion particles
    (Thesis (M.S.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2008., 2008.) Ezer, Cemile.; Arık, Metin.
    The Standard Model of particle physics has solved the problem of giving masses to quarks and leptons by introducing the Higgs particle which soon will be searched at the Large Hadron Collider at CERN. Another problem of the Standard Model is the strong CP violation problem which arises due to the interplay between the strong and weak sectors of the model. An understanding of this problem requires understanding the instantons and the quark mixing. In this thesis I present my understanding of these topics and consider how the strong CP violation problem can be solved by introducing the axion particle.