251,567 research outputs found
Discovery of Newly Formed Broad Absorption Lines in a Radio-Loud Quasar
We report a serendipitous discovery of broad absorption lines that were newly
formed in the spectrum of the high-redshift, luminous radio-loud quasar TEX
1726 + 344, in a time interval of only 12 years. This is the first quasar
showing a transition from narrow absorption lines to broad absorption lines. It
also becomes one of the few radio-loud broad absorption line quasars. The gas
cloud responsible for these broad absorption lines is derived to have
parameters coinciding with those of the remnant of a tidally disrupted star.Comment: 6 pages, 1 figure, accepted for publication as a Letter in Mon. Not.
R. Astron. So
Comment on ``Signal of Quark Deconfinement in the Timing Structure of Pulsar Spin-Down''
This is a comment on a paper by Glendenning, Pei, and Weber (Phys. Rev.
Lett., 79, 1603, 1997), where the authors gave an incorrect estimate of the
event rate and neglected the important gravitational energy release. Previous
work on the same subject is reviewed, and a new suggestion is made to link
quark-hadron phase transitions with soft gamma-ray repeaters.Comment: 4 pages; to appear in Phys. Rev. Let
The Steady-State Response of a Class of Dynamical Systems to Stochastic Excitation
In this paper a class of coupled nonlinear dynamical systems subjected to stochastic excitation is considered. It is shown how the exact steady-state probability density function for this class of systems can be constructed. The result is then applied to some classical oscillator problems
Evaluation of commercial GaN HEMTs for pulsed power applications
A non-conformally invariant coupling between the inflaton and the photon in the minimal Lorentz-violating standard model extension is analyzed. For specific forms of the Lorentz-violating background tensor, the strong-coupling and back-reaction problems of magnetogenesis in de Sitter inflation with scale are evaded, the electromagnetic-induced primordial spectra of (Gaussian and non-Gaussian) scalar and tensor curvature perturbations are compatible with cosmic microwave background observations, and the inflation-produced magnetic field directly accounts for cosmic magnetic fields
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