A Closer Look at the Anatomy of Spiral Galaxies

Stephan Peters

    Research output: ThesisThesis fully internal (DIV)

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    I have focused my research on spiral galaxies. The first part concerns the dark matter halo. Dark matter is a substance currently unknown to science. It is invisible and only reveals its presence due to the gravity it exerts on other objects. In my thesis, I have studied the shape of dark matter halos around so-called edge-on oriented spiral galaxies. I have developed new software with which I demonstrates that besides dark matter there is also a higher amount of regular gas, than previously expected. The shape of the halo varied drastic per galaxy. It remains unclear if this is a physical result, or that it is due to one of the many assumptions required in studying an invisible substance. I spend a considerable amount of time discussing all these assumptions.

    The second topic concerns the stellar disk. In the 1970s, it was shown that the stellar disk in spiral galaxies does not slowly fade with distance. Instead, there is a so-called truncation, beyond which the amount of stars rapidly drops to zero. This was discovered in edge-on galaxies, but has remained an elusive phenomenon in face-on galaxies to this day. I have shown that outer edges of galaxies are 'wobbly', causing these truncations to be blurred out. Only with high quality data, in combination with new software that I've developed, is it possible to detect these truncations in face-on galaxies.
    Translated title of the contributionEen nadere blik op de samenstelling van spiraalsterrenstelsels
    Original languageEnglish
    QualificationDoctor of Philosophy
    Awarding Institution
    • University of Groningen
    • van der Kruit, Pieter, Supervisor
    • Freeman, Ken C., Supervisor, External person
    • Allen, R, Supervisor
    Award date5-Sep-2014
    Place of Publication[S.l.]
    Print ISBNs978-90-367-7158-0
    Electronic ISBNs978-90-367-7157-3
    Publication statusPublished - 2014

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