Heavy neutrino balls and the supermassive dark object at the Galactic center
Includes bibliographical references. === Massive neutrinos were the first proposed, and still remain the most natural, particle candidate for the dark matter. We investigate here the properties and astrophysical implications of self-gravitating degenerate heavy neutrino matter. Neutrinos of 10 to 25...
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| Format: | Doctoral Thesis |
| Language: | English |
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University of Cape Town
2014
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| Online Access: | http://hdl.handle.net/11427/9886 |
| Summary: | Includes bibliographical references. === Massive neutrinos were the first proposed, and still remain the most natural, particle candidate for the dark matter. We investigate here the properties and astrophysical implications of self-gravitating degenerate heavy neutrino matter. Neutrinos of 10 to 25 keV/c² might cluster around the sun forming a halo of a few solar masses and a few light years radius. We calculate the perihelion shifts of planetary and asteroidal orbits that are expected due to the presence of a conjectured degenerate heavy neutrino halo around the sun. While the General Relativistic perihelion shifts are positive, those due to a possible dark matter halo are in general negative. A neutrino mass around ~16 keV is consistent with the observed mass excesses within the orbits of various outer planets, as obtailled from astrometrical data and Voyager 1 and 2 and Pioneer 10 and 11 ranging data. We then study the general relativistic effects on degenerate neutrino balls using the Tolman-Oppenheimer-Yolkoff (TOV ) equations of hydrostatic equilibrium. An extension of the TOV equations is made to describe the detailed properties of supermassive neutrino balls around compact objects such as white dwarfs and neutron stars. We further show that the supermassive compact dark object near Sgr A* at the Galactic center could be an extended object rather than a black hole. In fact these two scenarios can be distinguished by tracking the orbit of one of the fast moving stars near the Galactic center. VVe finally calculate the emission spectrum of the supermassive compact dark object using the standard accretion theory and show that the calculated radio wave to infrared emission spectrum between λ = 0.3 cm and λ = 10-³ cm is consistent with the observations. |
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