Observations from the 1930s until the present have established the existence of
dark matter with an abundance that is much larger than that of luminous matter.
Because none of the known particles of nature have the correct properties to be
identified as the dark matter, various exotic candidates have been proposed. The
neutralino of supersymmetric theories is the most promising example. Such cold dark
matter candidates, however, lead to a conflict between the standard simulations of
the evolution of cosmic structure and observations. Simulations predict excessive
structure formation on small scales, including density cusps at the centers of galaxies,
that is not observed. This conflict still persists in early 2007, and it has not
yet been convincingly resolved by attempted explanations that invoke astrophysical
phenomena, which would destroy or broaden all small scale structure. We have
investigated another candidate that is perhaps more exotic: Lorentz-violating dark
matter, which was originally motivated by an unconventional fundamental theory, but
which in this dissertation is defined as matter which has a nonzero minimum velocity.
Furthermore, the present investigation evolved into the broader goal of exploring
the properties of Lorentz-violating matter and the astrophysical consequences – a
subject which to our knowledge has not been previously studied. Our preliminary
investigations indicated that this form of matter might have less tendency to form
small-scale structure. These preliminary calculations certainly established that Lorentz-violating matter which always moves at an appreciable fraction of the speed
of light will bind less strongly. However, the much more thorough set of studies
reported here lead to the conclusion that, although the binding energy is reduced,
the small-scale structure problem is not solved by Lorentz-violating dark matter. On
the other hand, when we compare the predictions of Lorentz-violating dynamics with
those of classical special relativity and general relativity, we find that differences might
be observable in the orbital motions of galaxies in a cluster. For example, galaxies –
which are composed almost entirely of dark matter – observed to have enlarged orbits
about the cluster center of mass may be an indication of Lorentz violation.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1672 |
| Date | 15 May 2009 |
| Creators | Mondragon, Antonio Richard |
| Contributors | Allen, Roland E. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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