Redshift Of Spectral Lines Research Articles

Estimate of the Stark shift by penetrating ions within the nearest perturber approximation for hydrogenlike spectral lines in plasmas

Red shifts of spectral lines (hereafter, SL) play an important role in astrophysics. For inferring the relativistic red shifts from the observed red shifts it is required to allow for the Stark shift of SL. In laboratory plasmas, measurements of the Stark shift can supplement measurements of the Stark width and thus enhance plasma diagnostics—specifically the determination of the electron density. In the present paper we describe a new source of the Stark shift of hydrogenlike SL. It originates from configurations where the nearest perturbing ion is within the radiating atom/ion (‘penetrating configurations’). As an example, we compare the results with the experimental shift of the Balmer-alpha SL of He II 1640 A measured in a laboratory plasma by Pittman and Fleurier (1986 Phys. Rev. A 33 1291). We show that the allowance for this new additional red shift leads to a good agreement with the measured shift for the entire range of the electron density employed in that experiment, while without this new shift the previously known shifts underestimated the measured shift by factors between two and five.

Frequency Shifts of Spectral Lines Generated by Young's Pinhole Wave Scattering Upon a Quasi-Homogeneous Medium

Frequency shifts of light scattered from either a deterministic or random medium have shown great importance in remote sensing imaging applications, however, such scattering system which combines random scatterer with obstacles has not been specifically discussed so far. To solve this problem, we derive analytical expressions for showing the phenomenon that the Young's pinhole wave scattered from a quasi-homogeneous (QH) medium exhibits the red shift of spectral lines, while the first-order Born approximation is applied to treat the weak scattering between the diffractive wave and the medium. The shifted amount of spectrum is strongly dependent of the scattering angle, correlation length of the medium, and Young's pinhole parameter. Furthermore, we also observe that the red shift of the scattered spectrum converts to the blue shift when the correlation length reaches a certain magnitude. Through numerical simulations, analyses are performed on revealing the effects of Young's pinhole parameter and medium's correlation on the spectral shift and spectral switch of the scattered spectrum.

Is the Velocity Interpretation of the Redshift of Spectral Lines in Accordance with Astronomical Data?

Current progress in cosmic microwave background (CMB) anisotropy measurements opens up the possibility of determining Hubble’s constant (H0 = h × 100 km s−1 Mpc−1) from the CMB power spectrum radiation temperature anisotropy. The results show that, besides the Lambda cold dark matter (ΛCDM) model, much simpler Einstein-de Sitter (EdeS) models without the cosmological constant can fit the data as well, or even better, than the ΛCDM model. Calculations with EdeS models yield unexpectedly low values for Hubble’s constant of h = 0.30 and 0.46, respectively. These values are completely inconsistent with the direct determination of h ~ 0.70 from the redshift (RS) of spectral lines. In the present paper I consider whether the gap between h = 0.3 and h = 0.7 could be explained using conventional physics without introducing further hypotheses, or whether the RS of starlight and the RS of the CMB could stem from different physical origins.

Gravitational red shift and time delay of radar echo in f(R)-gravity

Sobouti proposes an action-based [Formula: see text] modification of Einstein’s gravity, which admits a similar Schwarzschild metric. A test star moving in such a space–time acquires a constant asymptotic speed at large distances. As we are concerned with two classical tests of Einstein’s theory which are gravitational red shift of spectral lines and time delay of radar echo passing the sun, we shall calculate them in the [Formula: see text]-gravity and show that the results are consistent with the experimental observation data.

Fringe structures and tunable bandgap width of 2D boron nitride nanosheets.

We report studies of the surface fringe structures and tunable bandgap width of atomic-thin boron nitride nanosheets (BNNSs). BNNSs are synthesized by using digitally controlled pulse deposition techniques. The nanoscale morphologies of BNNSs are characterized by using scanning electron microscope (SEM), and transmission electron microscopy (TEM). In general, the BNNSs appear microscopically flat in the case of low temperature synthesis, whereas at high temperature conditions, it yields various curved structures. Experimental data reveal the evolutions of fringe structures. Functionalization of the BNNSs is completed with hydrogen plasma beam source in order to efficiently control bandgap width. The characterizations are based on Raman scattering spectroscopy, X-ray diffraction (XRD), and FTIR transmittance spectra. Red shifts of spectral lines are clearly visible after the functionalization, indicating the bandgap width of the BNNSs has been changed. However, simple treatments with hydrogen gas do not affect the bandgap width of the BNNSs.

Static spherically symmetric star in Gauss—Bonnet gravity

We explore static spherically symmetric stars in Gauss-Bonnet gravity without a cosmological constant, and present an exact internal solution which attaches to the exterior vacuum solution outside stars. It turns out that the presence of the Gauss-Bonnet term with a positive coupling constant completely changes thermal and gravitational energies, and the upper bound of the red shift of spectral lines from the surface of stars. Unlike in general relativity, the upper bound of the red shift is dependent on the density of stars in our case. Moreover, we have proven that two theorems for judging the stability of equilibrium of stars in general relativity can hold in Gauss-Bonnet gravity.

Using of the Generalized Special Relativity in Deriving the Equation of the Gravitational Red-Shift

In this work we present a study of a new method to prove the equation of the gravitational red shift of spec-tral lines. That’s according to the generalized special relativity theory. The equation of the gravitational red shift of spectral lines has been studied in many different works, using different methods depending on the Newtonian mechanics, and other theories. Although attention was drawn to the fact that the well-known ex-pression of the gravitational Red-Shift of spectral lines may be derived with no recourse to the general rela-tivity theory! In this study a unique derivation has been done using the Generalized Special Relativity (GSR) and the same result obtained.

DO THE FUNDAMENTAL CONSTANTS CHANGE WITH TIME?

Comparisons between the redshifts of spectral lines from cosmologically-distant galaxies can be used to probe temporal changes in low-energy fundamental constants like the fine structure constant and the proton–electron mass ratio. Here, we review the results from, and the advantages and disadvantages of, the best techniques using this approach, before focussing on a new method, based on conjugate satellite OH lines, that appears to be less affected by systematic effects and hence holds much promise for the future.

Grebe/Bachems photometrische Analyse der Linienprofile und die Gravitations-Rotverschiebung: 1919 bis 1922

An effort of proponents of relativity theory to find evidence for the so-called gravitational red-shift of spectral lines as one of the experimental consequences of Einstein's generalized theory of relativity is reconsidered with reference to hitherto unpublished documents. It is shown how much interest Albert Einstein in fact took, around 1920, in the data analysis of Leonhard Grebe and Albert Bachem, who tried to explain why most earlier efforts to find the gravitational red-shift had failed. They carefully measured the line profiles of the spectral lines both in the sun's Fraunhofer lines and in pressure-independent laboratory comparison spectra. Then they rejected all lines with strong neighbouring lines which could cause apparent shifts of the line centres; the remaining seven well-isolated lines showed the gravitational red-shift with acceptable accuracy. Nevertheless, their claim to have successfully isolated the relativistic effect never convinced the astrophysicists of their day - the reasons for the scientific community's scepticism, contrasted against the enthusiastic group of Einstein sympathizers, are also discussed.

Red shift of spectral lines in the Sun's chromosphere

An unexplained center-to-limb variation (CLV) of solar wavelengths has been known for 75 years. A theory is described which not only explains this variation but also predicts its amplitude without the use of any adjustable parameter. The model considered is based on the fact that the momentum transfer of the solar photons to the electrons of the atoms of the solar atmosphere produces secondary radiation due to bremsstrahlung. The energy of this bremsstrahlung radiation is taken away from the energy of the initial photons and leads to a red shift. No ad hoc parameters are used, and all constants are either fundamental physical constants or well-known solar parameters. The model can explain the variation of the CLV as a function of its position on the disk and near the limb, and even the change in the lineshapes especially near the limb. >

New mechanism tor generating redshifts of spectral lines

New mechanism tor generating redshifts of spectral lines

Approximate theory of the red shift in conformally two-dimensional space

An account is given of the approximate theory of the red shift of spectral lines for a gravitational field described by a conforrnally two-dimensional space. This effect is interpreted as a consequence of different values of the gravitational potential at various points in the field, and it is not associated with the actual motion of the emitting bodies.

General relativity in Euclidean terms

The relativistic equations for the deflexion of light, the motion of a particle, and the red shift of spectral lines, in the neighbourhood of a single stationary mass, are rigorously derived on the basis of a strictly Euclidean space and an independent time. Only two ad hoc assumptions are needed, in addition to two very obvious extensions of the special theory; one of these assumptions is already familiar, but the other, involving the mass of a stationary test particle, is believed to be new. The particle equations are derived from a Lagrangian in the usual way. Expressions for the kinetic and potential energies are also readily obtained. It is shown (by what is believed to be a new argument) that matter with an infinite Young’s modulus cannot exist, and the fact that actual measuring rods may therefore be affected by tidal forces, even when they are ‘unconstrained’, is considered. It is shown that in principle observations in the solar system should be made in a time system which is not that in which the clocks of distant observatories are synchronized at present; the difference is below the present errors of the best time signals, but not very much below. A rigorous expression is derived for the numerical value of the radial co-ordinate r , in terms of quantities directly observable by the crew of a space-ship (of negligible mass) moving in a circular orbit at the appropriate circular velocity. Further progress along these lines will depend on their extension to the two-body problem.

Phenomenological linear theory of gravitation: Part III: Interaction with the spinning electron

A Lorentz-covariant, linear theory of gravitation interacting with the electromagnetic field as well as with matter has been developed in two preceding papers, in which matter was treated as consisting of classical point masses. Here, we treat the simultaneous interaction of this gravitational field with the electromagnetic field and with spinning electrons described wave-mechanically by Dirac's spinor or “undor” field. The “second” quantization of this undor field is postponed to Part IV of this series of papers. In the presence of the gravitational field, the usual interpretation of this undor field ψ as a probability amplitude needs modification. It is possible to define a field ϕ which takes the place of ψ as the probability amplitude. It is shown then that wave packets built up from these probability waves obey (but for some negligible spin terms) the same equations of motion as classical point particles in the “classical” limit in which both momentum and position of the wave packet are given with sufficient accuracy. The red shift of spectral lines emitted in a gravitational field is uniquely determined and is not influenced by the previously discussed uncertainty about the values of some of the constants in our Lagrangian. Our theory predicts for this red shift the same value as on quite different grounds is predicted by Einstein's theory. For both theories, there is no agreement between the predicted red shifts and the observed ones, probably as a result of other influences on the spectrum which are not fully understood.

A static cosmological model

A static cosmological model of the universe based onLyra's modified Riemannian Geometry is proposed. The red-shift of spectral lines from extra-galactic nebulae is shown to be a consequence of an inherent geometrical property of the model independent of expansion. The model is similar to the staticEinstein model but shows a red-shift and has a finite density even without the introduction of a cosmological constant.