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1.
It is shown that the Hubble curvem(z) for galaxies and quasars averaged over a large volume of data forms in the first approximation a single continuous curve in the interval of red shifts 10–2.5z4.5, which is satisfactorily described by the dependence .A large deviation of the observed mean dependence from the theoretical one predicted by the standard cosmology is explained by the evolution of the galaxy and especially quasar luminosity. The corresponding mid-statistical function of the absolute luminosity variation for the last 4/5 times of existence in the Universe is equal toM(z)–M(z 0)=logz/z 0+2z–0.4z 2.The luminosity of the most far distant from the observed quasars on the average by 5–6 stellar magnitudes high than the luminosity of near galaxies and quasars. It is obtained that even the most far distant quasars atz5 are in the maximum of luminosity, or their extinction has just began, thus the quasar formation should be expected forz>(5–6). The relative rate of the luminosity decrease of galaxies and near quasars is rather accurately amounts in the recent epoch 7% per 109 years. The obtained average Hubble curve of galaxies and quasars is evidently the main cause of their evolution in the Universe.  相似文献   

2.
An attempt has been made to solve the field equations with perfect fluid in an inhomogeneous space-time governed by the metric
in both Einstein and Barber's theories of gravitation. It is shown here that in both the theories the field equations are reducible to a Laplace equation and the perfect fluid distribution does not survive. Moreover all the solutions represent plane gravitational wave and the vacuum models in both the theories can be constructed by an arbitrary harmonic function iny and z coordinates. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

3.
R. Glass 《Solar physics》1982,80(2):321-331
Configuration interaction wavefunctions are used to calculate energy levels, wavelengths, oscillator strengths, line strengths, transition probabilities, lifetimes and branching ratios for absorption transitions between the 2lnl [n = 2, 3;l l] states for Si xi. Comparison with recent beam-foil experimental data for the 2s2p 1 P, 2p 2 1 D and 2p 2 1 S states is generally good, though in some cases cascade effects may be larger than had been expected.  相似文献   

4.
Parameters of the distant galaxy clusters of 3C295 (z=0.46) and Cl 0024+1654 (z=0.39) are compared with the predictions made using galaxies of the local clusters Coma (z=0.023) and DC 0329–52 (z=0.057) taking theK-effect into account. The distributions of colour and morphological type, and the amplitudesF +/F– of the 0 4000 discontinuity are examined and no evidence for evolution of the galaxies and the clusters can be seen.  相似文献   

5.
The interaction of the gravitational potential energy of a pair of overlapping Plummer-model galaxies is determined exactly for various separationsr of their centres. It is shown that the results can be well represented by the simple relationW(r)=–GM 1 M 2/(r 2+ 2)1/2, where 1/ is the average reciprocal distance between the stars of two galaxies of massesM 1 andM 2 when they have zero separation.  相似文献   

6.
In the bounds of a theoretical scheme treating consistently gravitational interaction as dynamical (gauge) field in flat space-time, an expression was obtained for the density of energy-momentum-tension of gravitational field in vacuum around a collapsed object. A case was studied of an interacting static spherically-symmetric field of a collapsar in vacuum with taking into account of input of all the possible components (spin states of virtual gravitons) into the energy for the symmetric tensor of second rank ik . The radius of the sphere filled by matter for the collapsar of massM may achieve values up toGM/c 2.  相似文献   

7.
A principally new, quantitative system of the classification of the spectra of planetary nebulae is proposed. Spectral class of excitation class of the nebulap is determined according to the relative intensities of emission lines (N 1+N 2) [OIII]/4686 HeII and (N 1+N 2) [OIII]/H (Table I, Figure 1). The excitation classes are obtained for 142 planetary nebulae of all classes—low (p=1–3), middle (p=4–8), and high (p=9–12+) (Tables II, III, and IV). An empirical relationship between excitation classp and mean radius of nebulae is discovered (Figure 2). This relationship as well as excitation classp, as an independend parameter, admit an evolutionary interpretation. It is shown that after reaching the highest class of excitationp=12+ the nebulae decrease their class of excitation with the further increases of sizes. The diagram of this relationship has two nearly-symmetric branches — rising and descending with the apogee onp=12+ (Figure 2).  相似文献   

8.
Comparison of the large-scale density and velocity fields in the local universe shows detailed agreement, strengthening the standard paradigm of the gravitational origin of these structures. Quantitative analysis can determine the cosmological density parameter, , and biasing factor,b; there is virtually no sensitivity in any local analyses to the cosmological constant,. Comparison of the dipole anisotropy of the cosmic microwave background with the acceleration due to theIRAS galaxies puts the linear growth factor in the range 0.6 /b = 0.6 –0.3 +0.7 (95% confidence). A direct comparison of the density and velocity fields of nearby galaxies gives = 1.3 –0.6 +0.7 , and from nonlinear analysis the weaker limit > 0.45 forb > 0.5 (again 95% confidence). A tighter limit, > 0.3 (4–6), is obtained by a reconstruction of the probability distribution function of the initial fluctuations from which the structures observed today arose. The last two methods depend critically on the smooth velocity field determined from the observed velocities of nearby galaxies by thePOTENT method. A new analysis of these velocities, with more than three times the data used to obtain the above quoted results, is now underway and promises to tighten the uncertainties considerably, as well as reduce systematic bias.  相似文献   

9.
A method for the determination of the background radiation temperature in earlier cosmological epochs at redshiftsz>2 is discussed in detail. The method is based on the fact that in the clouds situated at cosmological distances at redshiftz the background radiation temperature must be (1+z) times more than in the modern epoch (z=0). This shall affect the level populations of the atoms, ions and molecules and, consequently, the parameters of the absorption lines observed in quasar absorption spectra. It is proposed to use the transition3 P 0–3 P 1 ofCi (=610 ) for the measurement of the background radiation temperature. Atz>2 this absorption line shifts to the millimeter radio region and can be observed by radioastronomical methods.  相似文献   

10.
We consider the possibility that gravitational energy may play a local as well as global role in the behavior of matter in strong gravitational fields. A particular idealized equation, suggested as representing uniform energy density in general relativity, is examined, and its stability with respect to oscillatory and convective perturbations shown to be consistent with general relativistic hydrodynamics, subject to a new physical effect predicted for the behavior of fluids moving in strong fields. We calculate from this idealized equation the mass of a non-rotating neutron star, obtaining a maximum surface redshift ofz=2.48 and a maximum core mass of 9.79 14 –1/2 M. This compares withz=2.00 and 11.4 14 –1/2 M for a Schwarzschild star (=const.) and 6.8 14 –1/2 M for a causal star (dP/d1).  相似文献   

11.
By use of the dispersion equation given by Song, Wu, and Dryer (1987) for a cylinder plasma with mass motion and gravity included, we investigate the linear current instabilities developed in loop prominences. The results indicate that the mode of linear instability depends mainly on whetherv s 2 > or not, wherev s is the sonic velocity at heightz, =GM/(R +z) is the gravity potential,G the gravitational constant,M andR the mass and the radius of the Sun respectively. Ifv s 2 > , then the sausage instability will be dominant. Otherwise, the kink instability will be more important. A possible explanation of knot structure, which appears sometimes in solar loop prominences has been given.  相似文献   

12.
It is shown that inelastic proton collisions in extragalactic radio sources can account for their radio and -ray emissions. The proton Lorentz-factor p responsible for -ray emission is estimated to lie between 1.4 and 86. But for the radio emission (with e ~ 103-104) the estimated p values lie between 7 to 300. The estimates of total particle and magnetic energy for a typical radio source is in agreement with equipartition theory.  相似文献   

13.
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14.
A cosmological model describing the different stages of the universe, i.e.: inflation, radiation dominated period and matter dominated (Friedmann-like) period is shown. The model consists of the usual gravitational lagrangian with a R 2 term, and, for the matter content, the lagrangian of a massive conformally coupled scalar field. The effect of backreaction is evaluated by means of an extremum condition on the entropy at each time. The differential equation, obtained when the lowest quantum order is considered, describes all the periods of evolution of the universe. For a range of values of, inflation is unstable and the universe can reach the following regime.  相似文献   

15.
《New Astronomy》2002,7(7):373-384
  相似文献   

16.
An exact analysis of Hall current on hydromagnetic free convection with mass transfer in a conducting liquid past an infinite vertical porous plate in a rotating fluid has been presented. Exact solution for the velocity field has been obtained and the effects ofm (Hall parameter),E (Ekman number), andS c (Schmidt number) on the velocity field have been discussed.Nomenclature C species concentration - C w concentration at the porous plate - C species concentration at infinity - C p specific heat at constant pressure - D chemical molecular diffusivity - g acceleration due to gravity - E Ekman number - G Grashof number - H 0 applied magnetic field - j x, jy, jz components of the current densityJ - k thermal conductivity - M Hartman number - m Hall parameter - P Prandtl number - Q heat flux per unit area - S c Sehmidt number - T temperature of the fluid near the plate - T w temperature of the plate - T temperature of the fluid in the free-stream - u, v, w components of the velocity fieldq, - U uniform free stream velocity - w 0 suction velocity - x, y, z Cartesian coordinates - Z dimensionless coordinate normal to the plate. Greek symbols coefficient of volume expansion - * coefficient of expansion with concentration - e cyclotron frequency - dimensionless temperature - * dimensionless concentration - v kinematic viscosity - density of the fluid in the boundary layer - coefficient of viscosity - e magnetic permeability - angular velocity - electrical conductivity of the fluid - e electron collision time - u skin-friction in the direction ofu - v skin-friction in the direction ofv  相似文献   

17.
We discuss the winding of a force-free axisymmetric magnetic field rooted on a heavy conductor onz=0. In quadrupolar symmetry the field expands in the half-spacez>0 and the toroidal flux concentrates on a conical surface. After a mean twist of 208°, the conical layer hosts large toroidal current loops with reversal of the magnetic flux on either side. The evolution of the field structure is described by scale-free static solutionsBr –(p+2), withp taking values between 0 and 2. The large expansion factor of the field structure is suggestive of flaring originating on the solar photosphere.  相似文献   

18.
A further development of the Kostyuk-Pikelner's model is presented. The response of the chromosphere heated by non-thermal electrons of the power-law energy spectrum has been studied on the basis of the numerical solution of the one-dimensional time-dependent equations of gravitational gas dynamics. The ionization and energy loss for the emissions in the Lyman and Balmer lines have been determined separately for the optically thin and thick L-line layers. Due to the initial heating, a higher-pressure region is formed. From this region, disturbances propagate upwards (a shock wave with a velocity of more than 1000 km s-1) and downwards. A temperature jump propagates downwards, and a shock is formed in front of the thermal wave. During a period of several seconds after the beginning of this process, the temperature jump intensifies the downward shock wave and the large radiative loss gives rise to the high density jump ( 2/ 1 100). The numerical solution has been analyzed in detail for the case heating of the ionized and neutral plasma, and a value of this heating is close to the upper limit of the admissible values. In this case, the condensation located between the temperature jump and the shock wave front, may emit in the observed optical continuum.In their essential features, the gas dynamic processes during the flares in red dwarf atmospheres are the same as those in the solar atmosphere. However, the high atmospheric densities, smaller height scale in red dwarf atmospheres, and greater energy of this processes in stellar flares, give rise, in practice, to the regular generation of optical continuum. The photometric parameters of a source with n 015 cm-3, T 9000 K, and z 10 km are in a good agreement with observations.  相似文献   

19.
The variation of radio luminosity with redshift and its effect on the analysis of the angular size-redshift ( –z) relation for a bright radio source sample (s 178 10Jy) has been investigated. By assuming a power law dependence of luminosity on redshift of the formP (1 +z), it was found that 4.4 (with correlation coefficientr 0.99) for at leastz 0.3. Correction for such a strongP – (1 +z) correlation when considering the –z data for the sample led to a steeper –z slope. This could be explained by assuming linear size evolution of the formD (1 +z)–n withn = 2.8 – 3.3 consistent with both theoretical results and those obtained for more homogeneous source samples.  相似文献   

20.
The consequences of a cosmological term varying asS –2 in a spatially isotropic universe with scale factorS and conserved matter tensor are investigated. One finds a perpetually expanding universe with positive and gravitational constantG that increases with time. The hard equation of state 3P>U (U mass-energy density,P scalar pressure) applied to the early universe leads to the expansion lawSt (t cosmic time) which solves the horizon problem with no need of inflation. Also the flatness problem is resolved without inflation. The model does not affect the well known predictions on the cosmic light elements abundance which come from standard big bang cosmology.In the present, matter dominated universe one findsdG/dt=2H/U (H is the Hubble parameter) which is consistent with observations provided <10–57 cm–2. Asymptotically (S) the term equalsGU/2, in agreement with other studies.  相似文献   

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