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1.
2.
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   

3.
It is shown that the asymptotic σ1(r) and ψ1(r) relations can be derived very simply by using the method of double series expansion, where σ1, ψ1(r,0) and ψ1 are the surface density perturbation, the gravitational potential perturbation at the symmetric plane Z=0 and the average potential perturbation respectively. The results are accurate to the order of both m2(kr)?2 and k〈∣z∣〉, where m is the number of spiral arms, k is the radial wave number, r is the distance from the centre of the galaxy, and 〈∣z∣〉 is the average vertical distance of a star from the Symmetrie plane Z=0. Such an accuracy is usually sufficient for the discussion of spiral modes in a spiral galaxy of small but finite disk thickness. It is pointed out that ψ1(r,0)~(σ1(r) relation can be expressed in a unified form for different vertical density profiles if 〈∣z∣〉 is adopted as the thickness scale, and that ψ1(r,0)~(σ1(r) can be expressed in a unified form for different vertical density profiles if 〈∣z?z∣〉 the average vertical separation between two stars, is adopted as the thickness scale. Only the value of the ratio 〈|z?z′|〉z〈|z|〉 is a functional of the vertical density profile. However, for the usual physically meaningful profiles, these values are very close to each other: It is 2 for the Gaussian profile, 1Ln2 = 1.443 for the rmsech2(zz1(r)) profile, and 1.5 for the exp[?|z|z1(r)] profile.  相似文献   

4.
Published determinations of the deceleration parameter qo based on various selected subsets are reviewed and a uniform re-determination is made according to a procedure given in /1/.The resulting q0-values from 8 largely independant samples of radio quasars all fall within the 4σ range obtained in /1/, namely, 1.0 ? q0 ? 3.5. The most important assumption made is that the characteristic luminosity of radio quasars is independant of the cosmic epoch. Thus, unless radio quasars at earlier times were much more luminous than the later ones, the universe is probably closed.  相似文献   

5.
We have worked out a ’statistical algorithm’ for obtaining the posterior probability density of the deceleration parameter q0 from quasars where there is a luminosity indicator available. We point out that the role of the luminosity indicator is to provide asecond estimate of individual luminosities after a first estimate has been obtained from measured brightness and redshift together with an assumed q0. Discrimination of q0 is to be sought in the statistical properties of the set of differences between the two estimates (the residuals). We show that the variance of the residuals and their correlation with redshifts (further refined to luminosity distances) are two independent test-statistics for q0, whose known distributions then lead to the probability density sought. We have applied the above algorithm to a sample of flat-spectrum radio quasars with measured CIV, MgII and Ly α lines. A combined Baldwin’s relation was used for all 3 lines. Our result is that log q0 is normally distributed with a mean value of + 0.270± 0.135 (s.d.), or, q0 = + 1.86 ± 0.135 dex. This result, we believe, is the sharpest result so far published on q0.  相似文献   

6.
Using incoherent scatter data from Millstone Hill, we investigated the variations in the shape of the daytime, mid-latitude ionospheric electron density profile associated with changes in geomagnetic activity. The analysis performed was to deduce the dependence upon the 3-hr geomagnetic index Kp of h(Nm), h(0·7 Nm) above and below Nm, the plasma scale height HT in the range 500–1000 km, and the ratio N(1000)N(hm). The electron density data used spanned the solar maximum years 1968–1971. Daytime data from the period 1000 to 1600 LT were averaged separately for summer, winter and spring-fall. It is shown that the mean value M of the factor M = B cos θ sec χ used by Titheridge (1972) to relate the Faraday rotation Ω from a geostationary satellite to the total electron content NN up to 2000 km is practically the same (to within 1–2 per cent) as the M value used to relate the NT and Ω values both computed up to 1000 km. Taking advantage of this identity, we have used the linear relationship obtained between the ionospheric parameters and Kp to deduce the height at which M should be evaluated as a function of Kp.  相似文献   

7.
A ring current model has been obtained which permits calculations ofDst variations on the Earth's surface during magnetic storms. The changes in Dst are described by the equation
ddtDsto = F(EM)?Dstotau;
where Dsto = Dst-bp12+~tc; p = mnv2 is solar wind pressure; F(EM) is the function, controlled by the electromagnetic parameters of interplanetary medium, of injection into ring current ; τ is the constant of ring current decay. C = Cuτ?=18 nT, where C is the level of the Dst-variation field measurements; ? is the injection function characterizing the quasisteady-state injection of energy into the ring-current region. The constant Ç is determined from the condition that the change of the ring current energy from magnetic storm commencement to end should equal the difference between the injected and dissipated energy throughout the storm. The values of the factors b and τ were found by the method of minimizing the sum of the quadratic deviations of the calculated Dst from the values observed throughout the storm : b = 0.23 nT/(eV cm?3)12, τ = 8.2 h at Dst? ? 55 nT and τ = 5.8 h at -120 ? Dst ? — 55 nT. The injection function F(EM) is of the form F(EM) = d(Ey? A) at the values of the azimuthal component of the solar wind electric field Ey ? A, and F(EM) =0 at A?Ey.d = ? 1.2 × 10?3 Ts?1 (mV/m)?1 and A = ? 0.9 mV m?1 . Thus, the injection to ring current is possible at the northward Bz component of the IMF.  相似文献   

8.
It is demonstrated that the long term variation in cosmic ray intensity I(t) can be described by an integral equation,
I(t)=I?0f(τ)S(t?τ) dτ
, which is derived from a generalization of Simpson's coasting solar wind model. A source function S(t?τ) is given by some appropriate solar activity index at a time t?τ(τ ? 0) and the characteristic functionf(τ)(?0 forτ ? 0) expresses the time dependence of the efficiency of the intensity depression due to solar disturbances represented by S(t ?τ) when the disturbances generated at the solar surface propagate through the modulating region with the solar wind. It is demonstrated further that the equation can be derived from the general diffusion-convection theory on some assumptions, and as a result, the source and characteristic functions can be related to diffusion coefficient and its transition in space. Assuming the sunspot number R (or two activity indices including R) as the source function, the characteristic function f(τ) [or f(τ)'s] is obtained with data of the cosmic ray intensity extended over several decades. Based on the theory, one can obtain from f(τ) the following physical quantities in space, such as the transition and life time of solar disturbances, the boundary of the modulating region, and the radial and time dependences of the diffusion coefficient, radial density gradient and modulated intensity of cosmic rays. Results deduced from the present analysis are consistent with those obtained directly or indirectly by space observations.  相似文献   

9.
Observations of microwave opacity τ[λ] and near forward scatter from Saturn's rings at wavelengths λ of 3.6 and 13 cm from the Voyager 1 ring occultation experiment contain information regarding ring particle sizes in the range of about a = 0.01 to 15 m radius. The opacity measurements τ[3.6] and τ[13] are sufficient to constrain the scale factor n(a0) and index q of a power law incremental size distribution n(a) = n(a0)[a0/a]q, assuming known minimum and maximum sizes and a many-particle-thick model. The families of such distributions are highly convergent in the centimeter-size range. Forward scatter at 3.6 cm can be used to solve for a general distribution over the radius range 1 ? a ? 15 m by integral inversion and inverse scattering methods, again assuming a many-particle-thick slab-type radiative transfer model. Distributions n(a) valid over 0.01 ? a ? 15 m are obtained by combining the results from the two types of measurements above. Mass distributions may be computed directly from n(a). Such distributions, partly measured and partly synthesized, have been obtained for four features in the ring system centered at 1.35, 1.51, 2.01, and 2.12 Saturn radii (Rs). The size and mass distributions both cut off sharply at a ? 4–5 m; the mass distribution peaks over the narrow size range 3 ? a ? 4 m for all four locations. No single power law distribution is consistent with the data over the entire interval 0.01 ? a ? 5 m, although a power law-type model is consistent with the data over a limited size range of 0.01 ? a ? 1 m, where the indices q = 3.4 and 3.3 are obtained from the slab model for the features located at 1.51 and 2.01 Rs. The fractional contribution of the suprameter particles to the microwave opacity in each feature appears to be about 13, 13, 23, and 1, respectively, with the fraction at 2.12 Rs being the least certain. The cumulative surface mass per unit area obtained for the classical slab model is approximately 11, 16, 41, and 132 g/cm2 for the four features, respectively, if the particles are solid H2O ice. Both the fractional opacity and the mass density estimates represent upper bounds implied by the assumption of a uniformly mixed set of particles in a many-particle-thick vertical profile; lower estimates would result if the rings were assumed to be nearly a monolayer or if the vertical distribution of particles were size dependent.  相似文献   

10.
We study numerically and analytically the conditions leading to the truncation, at the 2:1 resonance, of a disk of infrequently colliding particles surrounding the primary of a binary system. We focus on systems with small mass ratios, q, such as the Sun-Jupiter system with q = 10?3. Previous studies showed that if collisions are frequent with respect to the orbital period, truncation 3nly occurs if the Reynolds number is greater than q?2. This corresponds to particle eccentricity, e, less than of order q for a particle disk of optical depth unity. In thepresent case collisions are less frequent than q?23 orbital periods (the period of the forced eccentricity at the 2:1 resonance), and truncation occurs and (Kirkwood) gaps are produced only if e is less than some critical value which we estimate to be of order q59, or ~0.02 for the Sun-Jupiter case. We mention several means whereby the eccentricities may have been subsequently increased to their observed values.  相似文献   

11.
Optical quasar candidate counts in the far reaching radio surveys B2 and 5C are consistent either with a luminosity function containing a high percentage of low luminosity objects and a cut off in quasar density or, more probably, with a normal number of quasars at high redshifts and a less steep luminosity function. The absence of high redshifted objects in currently available samples is to be expected of q0 ≈︂ o and if some of the few quasars observed at z>2.2 are exceptionally bright intrinsically and not typical for the bulk.  相似文献   

12.
Using the time observations obtained by 8 instruments in the Chinese Joint System during the years 1966–1980, we analyse the Moon's zonal tidal effect. The results show that the effects of the Mf and Mm waves are obvious. From this, the parameters KC of the zonal tide are estimated and the weighted averages of the 8 instruments are (KC)Mf = 0.909 ± 0.114 and (KC)Mm = 0.905 ± 0.083 respectively.  相似文献   

13.
Results are given of the calculations of the group delay time propagating τ(ω, φ0) of hydromagnetic whistlers, using outer ionospheric models closely resembling actual conditions. The τ(ω, φ0) dependencies were compared with the experimental data of τexp(ω, φ0) obtained from sonagrams. The sonagrams were recorded in the frequency range ? ? (0.5?2.5) Hz at observation points located at geomagnetic latitudes φ0 = (53?66)° and in the vicinity of the geomagnetic poles. This investigation has led us to new and important conclusions.The wave packets (W.P.) forming hydromagnetic whistlers (H.W.) are mainly generated in the plasma regions at L = 3.5?4.0. This is not consistent with ideas already expressed in the literature that their generation region is L ? 3?10. The overwhelming majority of the τexp values differ considerably from the times at which wave packets would, in theory, propagate along the magnetic field lines corresponding to those of the geomagnetic latitudes φ0 of the observation points. The second important fact is that the W.P. frequency ω is less than ΩH everywhere along its propagation trajectory, including the apogee of the magnetic force line (ΩH is the proton gyrofrequency). Proton flux spectra E ? (30?120) keV, responsible for H.W. generation, were determined. Comparison of the Explorer-45 and OGO-3 measurements published in the literature, with our data, showed that the proton flux density energy responsible for the H.W. excitation Np(MV622) ? (5 × 10?3?10?1) Ha2 where Ha is the magnetic field force in the generation region of these W.P. The electron concentration is Na ? (102?103) cm?3. The values given in the literature are Na ? (10?10?103) cm?3. The e data considered also leads to the conclusion that the generating mechanism of the W.P. studied probably always co-exists with the mechanism of their amplification.  相似文献   

14.
L. Trafton  D.A. Ramsay 《Icarus》1980,41(3):423-429
Observations of Uranus during the 1975, 1976, and 1978 apparitions reveal a weak absorption at the wavelength of the R5(1) line of HD with equivalent width 1.0 ± 0.4 mA?. The DH ratio in Uranus' atmosphere implied by this line and other published spectra is (4.8 ± 1.5) × 10?5, and may not be significantly different from that in the atmospheres of Jupiter and Saturn. In addition, the spectra exhibit two weak absorption at 6044.76 ± 0.02 and 6045.54 ± 0.02 A? which we were unable to identify. No trace of absorption is visible near these wavelengths or near the HD wavelength in a laboratory spectrum of 4.92 km-am CH4 which we obtained in an attempt to identify these absorption features and to verify that the HD feature does not arise from CH4.  相似文献   

15.
Results of impact fragmentation experiments for basalts and pyrophyllites are reported. Aluminum cylindrical projectiles were impacted on cubic basalt and pyrophyllite targets at velocities of 70 to 990 m/sec. The targets and projectiles were 20 g to 3.3 kg and 2 to 20 g in weight respectively. Weights of the fragments produced by impacts were measured and the size distributions of fragments were examined. Data of the largest fragment mass (mL) normalized to the original target mass (Mt), mL/Mt, correlate better with the nondimensional impact stress, PI, a new scaling parameter introduced by H. Mizutani, Y. Takagi, and S. Kawakami (1984, in preparation) than the conventional projectile's kinetic energy per unit target mass, E/Mt, used in the previous studies. All the mL/Mt data for basalts obtained in the present study are summarized by mL/Mt = 2.95 × 10?2PI?1 where PI = P0L3/YR3, P0 = peak shock pressure, L = projectile size, R = target size and Y = material strength of target. For aluminum targets, however, the mL/Mt is 2.5 orders of magnitude larger than that for brittle targets at impacts with the same PI. Size distributions of fragments expressed in a log N - log (m/Mt) diagram divided into three regimes bounded by two inflection points. In each regime the curve is expressed by N (>mMt) = A (mMt)?a. The slopes, a, of the log N - log (mMt) curves in the regimes of a large and a medium size range are positively correlated with the nondimensional impact stress, PI, and expressed as a = C3 + a3log PI. The slopes, a, in the smallest size range are, on the other hand, nearly constant and have values of 0.5 to 0.7 (12?23). Present results indicate that the impact fragmentation is scaled well by the new scaling parameter, PI, of Mizutani, Takagi, and Kawakami and that the present experimental data may shed new light on planetary impact processes.  相似文献   

16.
The expression for the zodiacal brightness integral is especially simple if the integrand contains the ‘directional scattering coefficient’, D, (a.u.?1), or equivalently the scattering cross-section per unit-volume. The two intersections of the terrestrial orbit with a line of sight lying in the ecliptic offer the possibility of isolating the contribution of the chord, with a conservative assumption of steadiness, but without the controversial assumption of a homogeneous zodiacal cloud. The zodiacal brightnesses between 60 and 120° elongation can be used to derive D0 and D, the value of D and its heliocentric radial derivative, both at 1 a.u. and at a scattering angle of 90°. A polarimetric treatment leads to the local polarization degree, P0, and to its heliocentric derivative, P. Applied to all three available observational sources, this method invalidates the assumption of homogeneity, leading to a rather high relative gradient PP0 near 1 a.u. (? 12, ? 16 or ? 24%, according to the source, as the Sun's distance decreases from 1.0 to 0.9 a.u.).The method is extended to Doppler spectrometry, taking advantage of the two equal projections on the line of sight of the Earth's velocity vector. The brightness Z0 and the Dopplershift Δλ0 observed at 90° elongation, together with the derivatives w.r.t. elongation ε, of the brightness, Z? and of the Dopplershift, Δλ, can be used to retrieve the mean orbital velocity, v, of the interplanetary scatterers in the region of the terrestrial orbit. The two most reliable observational sources lead, with fair agreement, to a relative excess (v ? V)V, over the terrestrial velocity, of the order of + 25%.  相似文献   

17.
W.W. Mullins 《Icarus》1978,33(3):624-629
A previous analysis of a stochastic model of lunar-type impact cratering is extended to utilize geological age data by defining a more general statistic Ωi(t) to be the number of equivalent whole craters of original diameter di and age ≤t in an observational area A; each crater is taken to be equivalent to the fraction of its rim (or area) that is in A and not occluded by later craters. By integration of a new gain-loss differential equation, a generalization of the previous basic equation is obtained that relates the expected value ωi(t) = E[Ωi(t)] to the process functions specifying the size distribution and flux of craters (primary or secondary) as they form. The results are specialized to the plausible case in which the cratered body can be subdivided into geological provinces of increasing ages t1, t2, …, ti … and the size probability distribution can be approximated as constant within each of the periods ti+1 - ti. It is shown that use of the Ωi permits, in principle, a reconstruction of the historical values of the process functions and correctly compensates for the effect of overlap by removing the false bias favoring large craters that results from the usual method of crater counting. Possible generalizations of the gain-loss equation are indicated.  相似文献   

18.
Substorm energy     
It is shown that the area Ak(× 106km2) covered by brightest auroras and the area Aq bounded by the auroral oval have a simple relation given by
Ak = 0.05(Aq ? A0)2
, where A0 denotes the area of the minimum size oval and the quantity (Aq ? A0)2 is proportional to the energy εq which is stored in the magnetotail and is available for substorms. Following the definition of the intensity of solar flares, Ak may be chosen as a measure of the intensity of substorms. It is also found that the joule heat energy produced by the auroral electrojet is also proportional to (Aq ? A0)2. Thus, it may be concluded that the intensity of substorms is proportional to the energy εq stored in the magnetotail.  相似文献   

19.
D.Chris Benner  Uwe Fink 《Icarus》1980,42(3):343-353
Laboratory band-model absorption coefficients of CH4 are used to calculate the Uranus spectrum from 5400 to 10,400 Å. A good fit of both strong and weak bands for the Uranus spectrum over the entire wavelength interval is achieved for the first time. Three different atmospheric models are employed: a reflecting layer model, a homogeneous scattering layer model, and a clear atmosphere sandwiched between two scattering layers. The spectrum for the reflecting layer model exhibits serious discrepancies but shows that large amounts of CH4 (5–10 km-am) are necessary to reproduce the Uranus spectrum. Both scattering models give reasonably good fits. The homogeneous model requires a particle scattering albedo (g?wp) ? 0.998 and an abundance per scattering mean free path (a?) ofa?1 km-am. The parameters derived from the sandwich layer model are: forsb the upper scattering layer a continuum single scattering albedo (g?w0) of 0.995 and a scattering optical depth variable with wavelength consistent with Rayleigh scattering; for the clear layer they are a CH4 abundance (a) of 2.2 km-am and an effective pressure (p) ? 0.1 atm; for the lower cloud deck a Lambert reflectivity (L) of 0.9 resulted. A severe depletion of CH4 in the upper scattering layer is required. An enrichment of CH4/H2 over the solar ratio by a factor of 4–14 in the lower atmosphere is, however, indicated.  相似文献   

20.
In this paper, we collect the redshift, bolometric luminosity, the full- width at half maximum of the Hβ emission line, the monochromatic luminosity at 5100 Å and the radio loudness for the sample of 117 quasars, including 20 radio-quiet quasars (RQQs) and 97 radio-loud quasars (RLQs). With the reverberation mapping method we calculate the black hole mass and Eddington ratio for this sample, as well as the radio luminosity from the total 5 GHz ?ux density. By analyzing the correlations among them, we obtain the following conclusions: (1) The black hole mass has weak correlations with the bolometric luminosity, radio loudness and radio luminosity for the RQQs, and has strong correlations with the bolometric luminosity, radio loudness and radio luminosity for the RLQs; (2) For the RQQs, the bolometric luminosity has weak correlations with the radio luminosity and 5 100 Å monochromatic luminosity, and for the RLQs, the bolometric luminosity has strong correlations with the radio luminosity and 5 100 Å monochromatic luminosity; (3) The RQQs and RLQs differ in the distributions of the black hole mass, emission line width and Eddington ratio. Based on these results, we suggest: the difference of emission line width between RQQs and RLQs is probably caused by the difference of black hole mass; the fundamental difference between RQQs and RLQs is caused by the difference of their intrinsic physical nature; the black hole mass, black hole spin, Eddington ratio, and host galaxy morphology are the important parameters to explain the origin of radio loudness and the double-peaked distribution; and the radio jet is closely related with the accretion rate of disk.  相似文献   

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