Density cusps: restrictions on non-axisymmetric models
نویسندگان
چکیده
منابع مشابه
Lens Models with Density Cusps
Lens models appropriate for representing cusped galaxies and clusters are developed. The analogue of the odd number theorem for cusped density distributions is given. Density cusps are classified into strong, isothermal or weak, according to their lens-ing properties. Strong cusps cause multiple imaging for any source position, whereas isothermal and weak cusps give rise to only one image for d...
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We construct three dimensional axisymmetric, cuspy density distributions, whose potentials are of Stäckel form in parabolic coordinates. As in Sridhar and Touma (1997), a black hole of arbitrary mass may be added at the centre, without destroying the Stäckel form of the potentials. The construction uses a classic method, originally due to Kuzmin (1956), which is here extended to parabolic coord...
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The hydrodynamics of a variant of classical BondiHoyle-Lyttleton accretion is investigated: a totally absorbing sphere moves at various Mach numbers (3 and 10) relative to a medium, which is taken to be an ideal gas having a density gradient (of 3%, 20% or 100% over one accretion radius) perpendicular to the relative motion. I examine the influence of the Mach number, the adiabatic index, and t...
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We investigated the dynamical reaction of the central region of galaxies to a falling massive black hole by N -body simulations. As the initial galaxy model, we used an isothermal King model and placed a massive black hole at around the half-mass radius of the galaxy. We found that the central core of the galaxy is destroyed by the heating due to the black hole and that a very weak density cusp...
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Context. The MHD instabilities can generate complex field topologies even if the initial field configuration is a very simple one. Aims. We consider the stability properties of magnetic configurations containing a toroidal and an axial field. In this paper, we concentrate mainly on the behavior of non-axisymmetric perturbations in axisymmetric magnetic configurations. Methods. The stability is ...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1998
ISSN: 0035-8711,1365-2966
DOI: 10.1046/j.1365-8711.1998.01413.x