منابع مشابه
Balmer line shifts in quasars
We offer a broad review of Balmer line phenomenology in type 1 active galactic nuclei, briefly summarising luminosity and radio loudness effects, and discussing interpretation in terms of nebular physics along the 4D eigenvector 1 sequence of quasars. We stress that relatively rare, peculiar Balmer line profiles (i.e., with large shifts with respect to the rest frame or double and multiple peak...
متن کاملStellar Surface Convection, Line Asymmetries, and Wavelength Shifts 1. Solar Line Asymmetries and Shifts
Wavelength positions of photospheric absorption lines may be aaected by surface convection (stellar granulation). Asymmetries and wavelength shifts originate from correlated velocity and brightness patterns: rising (blueshifted) elements are hot (bright), and convective blueshifts result from a larger contribution of such blueshifted photons than of redshifted ones from the sinking and cooler (...
متن کاملOn Elliptic Differential Operators with Shifts
The motivating point of our research was differential operators on the noncommutative torus studied by Connes [1, 2], who in particular obtained an index formula for such operators. These operators include shifts (more precisely, in this case, irrational rotations); hence our interest in general differential equations with shifts naturally arose. Let M be a smooth closed manifold. We consider o...
متن کاملA Parameter Uniform Numerical Scheme for Singularly Perturbed Differential-difference Equations with Mixed Shifts
In this paper, we consider a second-order singularly perturbed differential-difference equations with mixed delay and advance parameters. At first, we approximate the model problem by an upwind finite difference scheme on a Shishkin mesh. We know that the upwind scheme is stable and its solution is oscillation free, but it gives lower order of accuracy. So, to increase the convergence, we propo...
متن کاملPicosecond time-resolved measurements of dense plasma line shifts.
Picosecond time-resolved x-ray spectroscopy is used to measure the spectral line shift of the 1s2p-1s^{2} transition in He-like Al ions as a function of the instantaneous plasma conditions. The plasma temperature and density are inferred from the Al He_{α} complex using a nonlocal-thermodynamic-equilibrium atomic physics model. The experimental spectra show a linearly increasing redshift for el...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1980
ISSN: 0252-9211
DOI: 10.1017/s025292110007531x