Browsing by Author "Halliday, Samuel James Alexander"

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    The motion of stars and the accretion of matter in the fermion ball and black hole scenarios of the galactic centre
    (2003) Halliday, Samuel James Alexander; Viollier, Raoul
    The motion of stars SO-I, SO-2 and SO-4, in the vicinity of the galactic centre, is investigated using a X2 analysis of the parameters in our line of sight. The resulting phase spaces for the black hole and fermion ball scenarios are compared. We find that due to the lack of accurate z or Vz data, the upper limit of required observational time to discriminate between the scenarios is of the order 30 to 40 years. Such z and Vz data might allow us to eliminate one of the scenarios immediately. The spectrum from the Sgr A * region is also investigated using a simple Newtonian, optically thick and geometrically thin model for each scenario. As has already been known for some time, this technique is not applicable to a possible black hole scenario at Sgr A * and as a consequence, is incapable of explaining a cut-off in the spectrum at around 1013Hz. This cut-off follows naturally from the fermion ball potential distribution in this simple model. It should be noted that Advection Dominated Accretion Flow models (not investigated here) are able to predict the observed spectrum for the black hole scenario.