Physics and Astronomy

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Now showing 1 - 2 of 2
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    "Velocity Dispersion and Black Hole Mass in Seyfert 1 Galaxies"
    (2003) Nelson, Charles H.; Green, Richard; Bower, Gary; Gebhardt, Karl; Weistrop, Donna
    Bulge stellar velocity dispersions, sigma, in Seyfert 1 galaxies are combined with the M_bh -- sigma relation to validate reverberation mapping as a means of determining nuclear black hole masses. Seyfert galaxies follow the same relation as non-active galaxies, indicating that reverberation mapping is consistent with other methods. A similar result is obtained using new high resolution profiles of the [OIII] 5007 line for PG Quasars. Reconsidering the M_bulge - M_bh relation, we attempt to explain differences between Seyfert and non-active galaxies. We suggest that Seyfert bulges are systematically brighter than non-active galaxies, having lower M/L and younger stellar populations.
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    "Close-coupling and distorted-wave calculations for electron-impact excitation of the (5p56p) states of xenon"
    (American Physical Society, 2004-06) Bartschat, Klaus; Dasgupta, Arati; Madison, Don H.
    We report on a series of calculations for electron impact-excitation of the (5p^5)6p states in xenon from the ground state (5p^6)^1S_0. As in previous calculations for other noble-gas targets, we find strong evidence of channel coupling for all incident energies considered (between threshold and 200\,eV). Although qualitative agreement with the experimental results of Fons and Lin (Phys. Rev. A 58 (1998) 4603) is achieved, severe quantitative discrepancies of sometimes more than a factor of two remain.