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Linearized Perturbations of a Black Hole: Continuum Spectrum

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 نشر من قبل Alec Maassen van den Brink
 تاريخ النشر 2003
  مجال البحث فيزياء
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Linearized perturbations of a Schwarzschild black hole are described, for each angular momentum $ell$, by the well-studied discrete quasinormal modes (QNMs), and in addition a continuum. The latter is characterized by a cut strength $q(gamma>0)$ for frequencies $omega = -igamma$. We show that: (a) $q(gammadownarrow0) propto gamma$, (b) $q(Gamma) = 0$ at $Gamma = (ell+2)!/[6(ell-2)!]$, and (c) $q(gamma)$ oscillates with period $sim 1$ ($2Mequiv1$). For $ell=2$, a pair of QNMs are found beyond the cut on the unphysical sheet very close to $Gamma$, leading to a large dipole in the Greens function_near_ $Gamma$. For a source near the horizon and a distant observer, the continuum contribution relative to that of the QNMs is small.



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