Modification of the mean field theory of super-dense matter

We further discussed the Modified Mean Field Theory proposed in [1,2]. We found that this model has a new solution ml = 2; adding -meson, we calculated the symmetric energy of nuclear matter a₄; with the new parameters we calculated the equations of state with and without the addition of -meson; we compared the two; we also compared with the results for ml = 4.3; we made a preliminary theoretical investigation of the form of the vector meson mean field using the two-body correlation function; lastly, using the structural equation of neutron star we calculated the maximum mass for the various equations of state. The results are:

MMFT-2 (ml = 2): M_max = 2.22M (without -meson) M_max = 2.27M (with -meson)

MMFT-1 (ml = 4.3): M_max = 1.69M (without -meson) M_max = 1.89M (with -meson)

     

The angular momentum of a Kerr black hole

It is pointed out that, when calculating the angular momentum of a Kerr black hole, we should allow for the effect of accretion of scattered electrons in the retrograde direction. By using the radius of smallest circular orbit of the particle as a measure for the capture cross-section by the hole, the calculation is greatly simplified. Thorne's result, a/M = 0.9982, when retrograde photons are considered, is easily obtained. If we allow for retrograde electrons, we get a/M = 0.9986, if we allow for both retrograde electrons and photons, we get a/M = 0.9968; and if we further allow for pair annihilation, we get a/M = 0.9961.     

Magnetic classification of solar wind streams

It is found that from the viewpoint of the magnetic field configuration there are only two types of solar wind: streams with closed field lines (flare-induced streams) and streams with open field lines (M-streams of various velocity and lifetime, and quiet solar wind). We emphasize that in the absence of flare-induced streams the Earth's magnetosphere is, as a rule, circum-flown not by a quiet but by a variably disturbed solar wind—M-streams. An important feature of M-streams is that within a given interplanetary magnetic field sector the sign (+ or −) of the stream magnetic field almost always coincides with that of the sector. These facts lead to the conclusion that M-streams are mainly responsible for the sector structure.     

Robust limits on Lorentz violation from gamma-ray bursts

We constrain the possibility of a non-trivial refractive index in free space corresponding to an energy-dependent velocity of light: c(E)  c₀(1 − E/M), where M is a mass scale that might represent effect of quantum-gravitational space-time foam, using the arrival times of sharp features observed in the intensities of radiation with different energies from a large sample of gamma-ray bursters (GRBs) with known redshifts. We use wavelet techniques to identify genuine features, which we confirm in simulations with artificial added noise. Using the weighted averages of the time-lags calculated using correlated features in all the GRB light curves, we find a systematic tendency for more energetic photons to arrive earlier. However, there is a very strong correlation between the parameters characterizing an intrinsic time-lag at the source and a distance-dependent propagation effect. Moreover, the significance of the earlier arrival times is less evident for a subsample of more robust spectral structures. Allowing for intrinsic stochastic time-lags in these features, we establish a statistically robust lower limit: M > 0.9 × 10¹⁶ GeV on the scale of violation of Lorentz invariance.     

A combined photometric and spectroscopic solution for aa ursae majoris

From the photometric and spectroscopic data on AA UMa obtained by us in 1987 and 1986 and using the Wilson-Devinney program, we made a simultaneous solution. We found mass-ratio q = 1. 8157 ± 0.0099, M₁ = 0.85 M, M₂ = 1. 55 M , A = 3.39 R , R₁ = 1.50 R , and degree of over-contact f = 0.15 ± 0.01. Adding six minimum times obtained by us to the literature, a new epoch formula is derived: Min.I(J.D.Hel) = 2 446 885.1119+0.468 125 83 E.     

Spectroscopic orbits of eclipsing binaries: WX Cancri

We have determined for the first time a spectroscopic orbit for WX Cnc. The orbital elements are V₀ = +9.8 km/s, k₁ = 110.2 km/s, K₂ = 149.0 km/s, T_o = HJD 2446 480.0309. After combining with the published photometric results, we derive the the following absolute parameters: A = 6.32R, R₁ = 1.53R, R₂=1.18R, M₁ = 1.29 M, M₂ = 0.96M. The spectroscopic mass-ratio is q = 0.74.     

A spectroscopic orbit for the two—Spectrum eclipsing binary RT Persei

Intensified Reticon spectra have been obtained at a high dispersion for the Algol system, RT Persei. They were measured by the cross-correlation technique. The spectroscopic elements, revised for the primary component and determined for the secondary for the first time, are: T₀ = HJD 2,446,038.9332, K₁ = 55.0, K₂ = 194.7, V₀ = −8.3 km/s. A mass ratio q = m₂/m₁ = 0.282 is deduced. A circular orbit is adopted. The spectrum of the primary is F5V, and the secondary is a subgiant. With the elements determined here and the published photometric parameters, the absolute dimensions of the binary are: A = 4.20, R₁ = 1.20, R₂ = 1.08 R; M₁ = 1.08, M₂ = 0.30 M.     

Twilight effects of solar ionizing radiation

The absorption of solar ionizing radiation during twilight is investigated. Ion production rates are obtained as a function of altitude and twilight intensities and altitude profiles of emissions arising from the fluorescence of solar ionizing radiation are calculated for various solar depression angles. For an atmosphere with an exospheric temperature of 750°K, the predicted overhead intensity from fluorescence of the O⁺(²P — ²D) lines at 7319–7330 diminishes from 175 R at dusk to 10 R at a solar depression angle of 10°. The predicted overhead intensities from fluorescence of the N₂⁺ Meinel and first negative systems are respectively about 175 R and 20 R at dusk diminishing to respectively 1.5 R and 0.1 R at a solar depression angle of 10°.

It is suggested that a charge transfer reaction of O⁺²D in N₂ is a significant source of N₂⁺ ions. This reaction offers a possible explanation for the high apparent rotational temperatures in the first negative system observed by Broadfoot and Hunten. Other excitation and ionization mechanisms are briefly discussed.     

Synchrotron radiation from the Crab Nebula discriminates between models of space–time foam

It has been argued by Jacobson, Liberati and Mattingly that synchrotron radiation from the Crab Nebula imposes a stringent constraint on any modification of the dispersion relations of the electron that might be induced by quantum gravity. We supplement their analysis by deriving the spectrum of synchrotron radiation from the coupling of an electrically charged particle to an external magnetic fields in the presence of quantum-gravity effects of the general form (E/M_QG). We find that the synchrotron constraint from the Crab Nebula practically excludes 1.74 for M_QGm_P=1.2×10¹⁹ GeV. On the other hand, this analysis does not constrain any modification of the dispersion relation of the photon that might be induced by quantum gravity. We point out that such quantum-gravity effects need not obey the equivalence principle, a point exemplified by the Liouville-string D-particle model of space–time foam. This model suggests a linear modification of the dispersion relation for the photon, but not for the electron, and hence is compatible with known constraints from the Crab Nebula and elsewhere.     

Direction finding measurements of type III bursts in both elevation and azimuth

Direction finding measurements with the plasma wave experiments on the HAWKEYE 1 and IMP-8 satellites are used to find the source locations of type III solar radio bursts in elevation (geocentric solar ecliptic latitude) and azimuth (geocentric solar ecliptic longitude) in a frequency range from 31.1 kHz to 500 kHz. IMP-8 has its spin axis perpendicular to the ecliptic plane, hence by analyzing the spin modulation of the signals the location of the type III burst projected into the ecliptic can be found. HAWKEYE 1 has its spin axis nearly parallel to the ecliptic plane, hence the elevation of the source may also be determined. The trajectory of the electrons generating the burst, projected onto the ecliptic plane, follows an Archimedean spiral. Out of the ecliptic plane the trajectory is at a nearly constant heliographic latitude. The electrons originate from a region near a solar flare. With direction measurements of elevation and azimuth along with the modulation factor it is possible to determine the source size. Typical half angle source sizes range from 60° at 500 kHz to 40° at 56.2 kHz as viewed from the sun.     

The configuration of the loop-like structure of the solar atmosphere

An integral, governing steady flows in an isolated thin magnetic flux tube in the hydrostatic plane-stratified atmosphere, has been obtained. The integral, that we named as the shape integral, is expressed as (1 − M_A²)B cos θ = const. Here M_A² is the Alfven Mach number, B is the magnetic field strength and θ is the flux tube inclination to the horizontal. The shape integral should hold for most loop models because it represents just the momentum balance laws and has no relation to any energy balance mode. Its application to the isothermal and static cases is discussed and illustrated.     

Solar modulation of galactic cosmic-ray intensity as seen by neutron monitors during 1990–1999 – I. Rigidity Dependence and Correlations with Solar Activity Parameters

We analyze the evolution of cosmic ray intensity detected by six neutron monitors located at high altitude from 1990 to 1999, that includes most of solar cycle 22 and the start of cycle 23. This set of neutron monitors covers a wide range of geomagnetic cutoff rigidities. We discuss the most significant characteristics of the cosmic ray modulation during the period as: the extraordinary decreases produced by the events of the first half of 1991, the significant two step evolution of the recovery phase of solar cycle 22 and the start of cycle 23. We also determine the rigidity dependence of the different phases of the modulation cycle. Cosmic ray intensity correlations with several solar activity parameters as sunspots, microwave flux at 10.7 cm and solar flares and with the intensity of the interplanetary magnetic field are studied.     

Electro-hydromagnetic waves in a fully ionized gas-II

The propagation of hydromagnetic and low frequency radio waves in all directions in a fully ionized gas containing a magnetic field is examined. For longitudinal and transverse propagation the addition of one extra term in the magneto-ionic formulae (without collisions) accounts for the presence of heavy ions.

The partition of energy of disturbance between kinetic (K) and magnetic (M) for longitudinal propagation of all frequencies is given by

where V is the Alfvén speed. Thus approximate equipartition may exist for some audio- and radio-frequencies in the Earth's exosphere.

Some errors in Paper I of this series are corrected.     

Adiabatic vibrational frequencies of local and nonlocal convection models of the sun

The eigen-vibrational frequencies of Xiong Da-run's nonlocal and local convection models of solar envelope are calculated and compared. The differences between the observational and theoretical vibrational frequencies are less than 1%. They can be divided into two isolated groups. For modes with l ≥ 60, all the differences between observed and theoretical eigen-vibrational frequencies are distributed in a narrow and inclined belt in the (Δv ≈ v)-diagram. This shows that the theoretical model of solar convective region can approximately reflect the intrinsic structure of the sun in the region of r = (0.70–0.95)R. The discrepancies between the theoretical and observational frequencies come from the outer layers. For modes with l < 60, the theoretical vibrational frequency is smaller than the observational one. This implies that the temperature of the upper part of the convectively unstable region is rather low. The frequency difference is more dispersed in the local convection model than in the nonlocal convection model. For the intermediate- and low-frequency ranges (v < 3000), the difference between the two models is small, while for the high-frequency range (v ≥ 3000) the frequency in the local model is higher than in the nonlocal model. This means that the temperature of the radiation region beneath the convective region is higher in the local convection model than in the nonlocal convection model. The nonlocal model is nearer to the observation than the local model.     

Manifestation of solar activity in solar wind particle flux density

An analysis has been made of the origin of long-term variations in flux density of solar wind particles (nv) for different velocity regimes. The study revealed a relationship of these variations to the area of the polar coronal holes (CH). It is shown that within the framework of the model under development, the main longterm variations of nv are a result of the latitude redistribution of the solar wind mass flux in the heliosphere and are due to changes in the large-scale geometry of the solar plasma flow in the corona.

A study has been made of the variations of nv for high speed solar wind streams. It is found that nv in high speed streams which are formed in CH, decreases from minimum to maximum solar activity. The analysis indicates that this decrease is attributable to the magnetic field strength increase in coronal holes.

It has been found that periods of rapid global changes of background magnetic fields on the Sun are accompanied by a reconfiguration of coronal magnetic fields, rapid changes in the length of quiescent filaments, and by an increase in the density of the particle flux of a high speed solar wind. It has been established that these periods precede the formation of CH, corresponding to the increase in solar wind velocity near the Earth and to enhancement of the level of geomagnetic disturbance.     

Solar-cycle dependence of galactic cosmic ray flux

To investigate the relationship between solar activity and cosmic ray modulation, time series of the nucleonic flux and of solar plages, sunspots, centimeter radio noise, and the brightness of the white light corona at 1.1 and 1.5 solar radii from the center of Sun are cross-correlated. Data pertain to the years 1964–1967 during the ascending phase of the current solar cycle. The amplitudes and phases of correlation functions for filtered and unfiltered indices are discussed. The existence of a superior solar index for relating solar activity to long-term modulation is not yet demonstrated conclusively, and the time lag of modulation is too poorly determined to permit its use in estimating the radius of the modulation region.Presently at the Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

Properties of the infrared dark cloud G79.2+0.38

The MSX infrared dark cloud G79.2+0.38 has been observed over a 11′×′ region simultaneously in the J=1-0 rotational transition lines of the ¹²CO and its isotopic molecules ¹³CO and ¹⁸CO. The dense molecular cores defined by the C¹⁸O line are found to be associated with the two high-extinction patches shown in the MSX A-band image. The two dense cores have the column density N (H₂) (5 – 12) × 10²² cm⁻² and the mean number density n (3 ± 1) × 10⁴ cm⁻³. Their sizes are 1.7 and 1.2 pc in ¹³CO(1-0) line, 1.2 and 0.6 pc in C¹⁸O(1-0) line, respectively. The masses of these cloud cores are estimated to be in the range from 2 × 10² to 2 × 10³ M. The profile of radial mean density of the cloud core can be described by the exponential function ¯n(p) p^{−0.34±0.02}. Compared with the cases of typical optical dark clouds, the abundances of the CO isotopic molecules ¹³CO and C¹⁸O in this MSX infrared dark cloud appear to be depleted by a factor of 4–11, but at present there is no evidence for any obvious variation of the relative abundance ratio X_13/18 between ¹³CO and C¹⁸O with the column density.     

Galactic gamma halo by heavy neutrino annihilations?

The diffused gamma halo around our Galaxy recently discovered by EGRET could be produced by annihilations of heavy relic neutrinos N (of fourth generation), whose mass is within a narrow range (M_Z/2<m_N<M_Z). Neutrino annihilation in the halo may lead to either ultrarelativistic electron pairs whose Inverse Compton Scattering on infrared and optical galactic photons could be the source of observed GeV gamma rays, or prompt 100 MeV–1 GeV photons (due to neutral pion secondaries) born by reactions. The consequent gamma flux (10⁻⁷–10⁻⁶ cm⁻² s⁻¹ sr⁻¹) is well comparable to the EGRET observed one, and it is also compatible with the narrow window of neutrino mass 45 GeV <m_N<50 GeV, recently required to explain the underground DAMA signals.The presence of heavy neutrinos of fourth generation do not contribute much to solve the dark matter problem of the Universe, but may be easily detectable by outcoming LEP II data.     

The regimes of the east-west and the radial anisotropies of cosmic rays in the heliosphere

The observations obtained over the last 23 y suggest that there are two distinct physical states of the heliosphere. One state covers the period 1957–1970 when the diurnal anisotropy consists of the azimuthal component only. One may define this period as the regime of the East-West (co-rotation) anisotropy. The period 1971–1979 is characterized by the appearance of a radial anisotropy, which attains a maximum amplitude in 1976, when the solar activity is minimum. There appears to exist an inverse correlation between the amplitude of the radial anisotropy and solar activity. The amplitude of the EastWest anisotropy varies with time during this latter period and may also be rigidity-dependent. In 1976 the amplitude of the East-West anisotropy is zero for the underground muon data obtained at Embudo and has a lower value for the neutron monitor data obtained at Deep River. On the other hand, the amplitude of the radial anisotropy depends weakly upon the primary rigidity. The period 1971–1979 thus defines the regime of the radial anisotropy. The physical state of the heliosphere is very stable during the regime of the East-West anisotropy and extremely dynamic during the regime of the radial anisotropy. The heliosphere appears to switch from one physical state to another following the onset of the solar polar field reversal.     

Nature of solar-cycle and heliomagnetic-polarity dependence of cosmic rays, inferred from their correlation with heliomagnetic spherical surface harmonics in the period 1976–1985

Correlation of cosmic-ray intensity (I) with the solar magnetic field expanded into the spherical surface harmonics, B_ns(n 9), by Hoeksema and Scherrer has been studied using the following regression equation:

, where are subgroups of B_ns classified in ascending order of n, and τ_i is the time lag of I behind correlation coefficient between the observed and simulated intensities (I_obs, I_sml) in the period 1976–1985 is 0.87 and considerably better than that derived from any single index of solar activity. The lag time τ₃ is greater than others, indicating that the higher order magnetic disturbances effective to the cosmic-ray modulation have a longer lifetime in space than the lower order disturbances. The rigidity spectrum of the cosmic-ray intensity variation responsible for A_I due to the dipole moment is harder than those for others (A₂,A₃), indicating that the lowest order (i.e. largest scale) magnetic disturbances can modulate cosmic rays more effectively than the higher order disturbances. As another result of the present analysis, it has been found that the intensity depends also on the polarity of the polar magnetic field of the Sun; the residual (I_obs−I_sml) of the simulation changes its sign from positive to negative with a time lag (0–5 Carrington rotation periods) behind the directional change of the solar magnetic dipole moment from northward to southward, and has a softer rigidity spectrum than A_iS. The dependence is consistent with the result having been obtained in the previous period, 1936–1976, by one (K.N.) of the present authors. The polarity dependence can be found also in the 22-year variation of the time lags obtained every solar cycle in the period 1936–1985. The theoretical interpretation of these polarity dependences is discussed on the basis of the diffusion-convection-drift model.