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1.
A maximal spectrum of gravitational radiation from sources outside our galaxy is calculated. The sources are galaxies, quasars and events that occur in the early history of the universe. The major contribution is from galaxies whose effect extends over the frequency region 10–810+4Hz, peaking at 10–110 Hz, with a spectral flux of 10 erg cm–2, s–1. The main processes of gravitational radiation in the galaxies are stellar collapse into a black hole and dying binary systems. In the region 10–4104 Hz the background spectrum is well above the detection levels of currently proposed detectors. FromMinimal considerations of this spectrum it is determined that the density of gravitational radiation is 10–39g cm–3. This background spectrum is sensitive to galactic evolution and especially sensitive to the upper mass limits and mass distribution of stars in galactic models. Therefore, the spectrum could provide information about galactic evolution complementary to that obtained by electromagnetic investigations.  相似文献   

2.
Conclusions In the Newtonian case we have obtained an isotropic self-consistent distribution of gravitationally interacting point masses which satisfies the transport equation without collisions, and the gravitational equation for an arbitrary powerfunction density distribution =r–s, s<3.For =r–2 the analogous self-consistent solution was obtained for the anisotropic distribution function both in Newtonian and GTR cases.The GTR solutions with =r–2 have central redshifts which increase without limit in accordance with the law 1+zr–1/ as we approach the center. In the isotropic case, they appear to be stable when the mean velocities are much less than the velocity of light u<0.2c, >21.The hydrodynamic GTR solution was found for a perfect gas at constant temperature (but variable T=T(g00)1/2) which also has z for r0.We should like to thank K. Thorne, L. Hazin, and M. Podurets for valuable discussions. K. Thorne was particularly helpful in supplying unpublished results on circular orbits obtained by American authors.Astrofizika, Vol. 5, No. 2, pp. 223–234, 1969  相似文献   

3.
A spectral analysis of the time series of daily values of 12 parameters, namely, ten solar radio emissions in the range 275–1755 MHz, 2800 MHz solar radio flux, and sunspot numbers for six continuous intervals of 132 values each during June 1997–July 1999 showed considerable differences from one interval to the next, indicating a nonstationary nature. A 27-day periodicity was noticed in Interval 2 (26.8 days), 3 (27.0 days), 5 (25.5 days), 6 (27.0 days). Other periodicities were near 11.4, 12.3, 13.3, 14.5, 15.5, 16.5, 35, 40, 50–70 days. Periodicities were very similar in a large vertical span of the coronal region corresponding to 670–1755 MHz. Above this region, the homogeneity disappeared. Below this region, there were complications and distortions due to localized solar surface phenomena.  相似文献   

4.
Macrospicules have been observed in H and He i D3, on the disk and above the limb. In 1975, a rate of 1400 (A day)–1 is inferred, and the ratio of equatorial to polar rates 2. D3 intensities are a few × 10–3 of the disk center, and do not decrease in coronal holes. The ratio of H to D3 intensities is 10. The integral number of macrospicules with D3 intensity I 0 is proportional to I 0 –1.  相似文献   

5.
We investigate the role of the cosmological constant in the formation of neutrino halos. Using the observational limit 10–55 cm–2 we find that it is relevant only for neutrinos of very light rest-mass: namely, 10–1 eV.On leave of absence from Department of Physics, College of Mines, Ostrava, Czechoslovakia.  相似文献   

6.
The analysis of solar wind He++ and H+ ion distribution functions, collected over five months by the satellite Prognoz 1, shows that these are in general maxwellian but that often tails appear at higher speeds. The existing relation V-T, the observation of ratios of T/Tp 3.83 and V/Vp 1.035 give evidence of preferential He++ ion heating and acceleration. The criteria for heating by dissipation of hydromagnetic waves proposed by Barnes and Hung (1973) are tested experimentally. Finally, multifluid models are likely to predict certain observations such as dependence of the velocity ratio V/Vp on the solar wind flux.  相似文献   

7.
Attention is given to the radiation of microwaves by charged dust in space. Presently-used particle distributions do not restrict the presence in space of large numbers of small (r<10–6 cm) silicate grains, but it is shown that such densities (10–25–10–26 g cm–3) of small grains would produce a microwave background with an energy density of the same order of magnitude as the energy density of the (presumed) cosmological 3 K background. Limits set by the isotropy of the latter are: (HI clouds)10–26, (Galactic plane)10–30, (Halo)10–32, (Local Group)10–34 g cm–3. These limits imply that either there is a cutoff in particle distributions atr10–6 cm, or that the density of silicate grains in space has been generally overestimated, or that cosmic rays have broken up a lot of grains so that they now form a population of grains of very small size (10–7 cm) which are difficult to detect by conventional methods. One way to look for the latter population is by studying expected distortions of the 3 K spectrum to the short wavelength side of the portion hitherto observed (grains may have a size distribution able to give an approximate black-body curve for radiation from larger grains of 10–6 cm size), and by testing the effective energy density of the 3 K field in other galaxies.  相似文献   

8.
Vector magnetogram, H, and hard X-ray observations of flares are reviewed which show that nonthermal electron signatures in H are never cospatial with regions of maximum current density for the small number of flares analyzed, but lie to the sides of these regions. By considering electron acceleration and transport requirements, four conditions are found that must be fulfilled to observe nonthermal electron signatures in H: (1) The plasma beta 0.3 in the acceleration region. (2) The energy flux of electrons above 20 keV is greater than 1010 erg cm–2 s–1. (3) The column densityN 1020 cm–2 between the electron source and the chromosphere. (4) The coronal pressure in the flux tube connecting to the H layerp 100 dyne cm–2. Condition 2 can be most easily met in the initial stages of flares. In contrast, the only condition for a high-pressure H signature isp 1000 dyne cm–2, which is most easily met in a region of maximum current density or heating and far enough into the flare for significant heating to have occurred. Thus, high-pressure signatures should be expected to occur more frequently than nonthermal electron signatures and to occur generally later in time.Also Guest Worker at NOAA Space Environment Laboratory Boulder Colorado U.S.A.  相似文献   

9.
Spherically symmetric, steady-state, optically thick accretion onto a nonrotating black hole with the mass of is studied. The gas accreting onto the black hole is assumed to be a fully ionized hydrogen plasma withn 0=108 cm–3 andT 0=104 K far from the black hole, and a new approximate expression for the Eddington factor is introduced. The luminosity is estimated to beL=1.875×1033 erg s–1, which primarily arises from the optical surface (1) ofT104 K. The accretion flow is characterized by 1 and (v/c)10. In the optically thin region, the flow remains isothermal, and the increase of temperature occurs at 1. The radiative equilibrium is strictly realized at (v/c)10.  相似文献   

10.
We present the analysis of spectrograms obtained during quiescence and during an ordinary outburst of the SU UMa type dwarf nova WX Hyi (ESO 3.6m telescope, B&C spectrograph with Image Disector Scanner, 171 Åmm–1, range 4000–7000 Å, time resolution 6min.). The radial velocities of these spectra have been discussed by Schoembs and Vogt (1981) who also derived the orbital elements of WX Hyi. The phasesmax refer to these elements. All velocities discussed here are with respect to the white dwarf, not to the center of mass of the binary system.Inquiescent state we did not find significant radial velocity variations. The equivalent widths W of the He I emission lines revealed periodic variations with an amplitude of 30%, maximal values of W were observed atmax=0.0...0.2. In contrast, the equivalent widths of the Balmer lines were not variable.Duringoutburst we found periodic radial velocity variations of the emission peak of H, H and He I 5875 with an amplitude of100 km s–1,max0.5. Also the broad Balmer absorption lines revealed periodic radial velocity variations, with a similar amplitude (max=0.3...0.5). The equivalent width of the H central emission peak varies with an amplitude of30%,max0.85. No variations of the equivalent width of the Balmer absorption lines were found.The outburst observations suggest that the preceeding part of the disc is brighter than the following one (in orbital motion). This is probably due to heating of the preceeding part by collisions with circumbinary matter, which seems to have an enhanced density in outburst as compared to the quiescent state. The emission lines are formed in outer layers or in a halo around the disc. The equivalent width variations can be interpreted in terms of interactions between this halo and the optically thick part of the disc.A more detailed discussion of the data is being published elsewhere.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986  相似文献   

11.
A computer routine using rigorous Güttler theory was developed to consider effects of concentric cavities and organic mantles within and around graphite spheres, with a view to assessing the stability of the extinction peak near 4.60 m–1. The newly discovered stable carbon molecule of 60 atoms gives an absorption band at 4.60 m–1 which closely agrees with the observed; moreover, it leads to the observed extinction rise in the far UV and can possibly explain the fine structure around the 5.5–7 m–1 dip, while its own structure deals successfully with the main objections to previous carbon-graphite models. The role of the electric vector component perpendicular to the basal plane of the crystal in achieving the fit is stressed.  相似文献   

12.
You  Jianqi  Hiei  Eijiro  Li  Hui 《Solar physics》2003,217(2):235-245
After carefully comparing the white-light (5600±00 Å) and the slit-jaw H images (0.5 Å  passband) of the 2N/X20 white-light flare of 16 August 1989, we found that the H counterpart identification of the bright kernels in continuum by Hiei, Nakagomi, and Takuma (1992) was incorrect. Now we come to the conclusion that none of the two white-light kernels has a corresponding bright H area. Moreover, the loop shapes in white-light are also different from those in H. H loops rose more rapidly than white-light loops. However, their height–time variations on the whole are similar. This indicates that the continuum and chromospheric emissions of the flare presumably come from different plasmas, but may be modulated by some mutual factors, such as large-scale magnetic fields. Analysis of the Hei 10830 Å spectra taken simultaneously with the slit-jaw H images shows that the line-center intensity of Hei 10830 Å doesn't have a good correlation with the intensity of nearby continuum, which supports the above conclusions. In addition, the electron density at the white-light loop top estimated from the continuum around 5600 Å  and 10830 Å  is as high as 1012–1013 cm–3.  相似文献   

13.
A charged particle detector array flown on a high altitude balloon has detected and measured some 3×104 cosmic-ray nuclei withZ12. The charge spectrum at the top of the atmosphere for nuclei withE>650 MeV·n–1 and the energy spectrum for 650E<1800 MeV·n–1 are reported and compared with previously published results. The charge spectrum at the source of cosmic rays is deduced from these data and compared with a recent compilation of galactic abundances.  相似文献   

14.
In this paper, series of rigid Mars nutations for the angular momentum axis, the rotation axis and the figure axis, as well as series of rigid Mars tide generating potential (TGP) are computed. The method used is based on the calculation of the forces produced by the external bodies on the rigid Mars. We have included the direct effect of the sun, Phobos and Deimos. We have also included the indirect effects associated with these bodies and planets of the Solar System which are given at the level of the ephemerides. For the nutation series, with a truncation level of 0.1mas (milliarcsecond), related to the present-day precision of the Martian precession constant, 24 terms in longitudes (*****) and 10 terms in obliquity (*****) are computed. The value of the dynamical flattening used is H D=(C–A)/C=0.00536, derived from the value p a=–7576±35mas/yr for the precession rate. Our results show a perfect agreement with those of Bouquillon and Souchay (1996) to the truncation level of Bouquillon and Souchary (1mas). For the TGP series, we have set the truncation level to 10–6m2/s2 which corresponds to an effect on the vertical acceleration on Mars surface of about 10–12m/s2=0.1nanogal (1nanogal=10–11m/s2. With this truncation level, 134 terms are computed.  相似文献   

15.
Type III radio bursts observed at kilometric wavelengths ( 0.35 MHz) by the OGO-5 spacecraft are compared with > 45 keV solar electron events observed near 1 AU by the IMP-5 and Explorer 35 spacecraft for the period March 1968–November 1969.Fifty-six distinct type III bursts extending to 0.35 MHz ( 50 R equivalent height above the photosphere) were observed above the threshold of the OGO-5 detector; all but two were associated with solar flares. Twenty-six of the bursts were followed 40 min later by > 45 keV solar electron events observed at 1 AU. All of these 26 bursts were identified with flares located west of W 09 solar longitude. Of the bursts not associated with electron events only three were identified with flares west of W 09, 18 were located east of W 09 and 7 occurred during times when electron events would be obscured by high background particle fluxes.Thus almost all type III bursts from the western half of the solar disk observed by OGO-5 above a detection flux density threshold of the order of 10–13 Wm–2 Hz–1 at 0.35 MHz are followed by > 45 keV electrons at 1 AU with a maximum flux of 10 cm–2 s–1 ster–1. If particle propagation effects are taken into account it is possible to account for lack of electron events with the type III bursts from flares east of the central meridian. We conclude that streams of 10–100 keV electrons are the exciting agent for type III bursts and that these same electrons escape into the interplanetary medium where they are observed at 1 AU. The total number of > 45 keV electrons emitted in association with a strong kilometer wavelength type III burst is estimated to be 5 × 1032.  相似文献   

16.
The life-time of the star on AGB is approximately 6 × 104 yr. We divide it into front half and back half of AGB (including to optical Mira variable and OH/IR star) according to their evolution character. The observations show that the star has non-pulsation, but constant mass loss rate ( 5 × 10–7 M yr–1) on front half of AGB. Its circumstellar envelope is formed. When the star has pulsation on back half of AGB, its mass loss rate is relative with time, and increases gradually. In this time the star is on the stage of optical Mira variable. When the mass loss rate reaches the value of 3 × 10–6 M yr–1, the star evoluted from the stage of optical variable into the stage of radio bright OH/IR star. On the end of AGB the mass loss rate reaches 10–4 M yr–1. (Band and Habing 1983, Hermen and Habing 1985).  相似文献   

17.
Surface photometry of the UV continuum galaxy NGC 838 has been carried out in theB, V system using photographic plates obtained with the 74 Kottamia telescope, Egypt. Isophotes, luminosity profiles, integrated photographic magnitudes, effective diameters and other photometric parameters are derived.The photoelectrically calibrated total apparent magnitudes areB T =13.57 with maximum diameters 1.57×1.34 (at threshold m =27.7 mag.//) andV T =12.91 with maximum diameters 1.54×1.32 (at threshold m =27.7 mag./). The integrated colour index(B–V) T =0.66 and the effective surface brightness e (B=19.0 mag./) and e (V=19.7 mag./. The major axis is at position angle =85°±1°.The nucleus of NGC 838 is quite blue (integrated colour(B–V)=0.41 forr *<0.1) compared to normal galaxies while the colour becomes redder from the nucleus outwards. The UV excess, H emission and radio continuum emission previously observed from this galaxy by other investigators may be attributed to a recent burst of star formation in the nucleus of the galaxy of duration slightly greater than 2×107 yr.  相似文献   

18.
We have studied the thermonuclear runaways which develop on white dwarfs of 1.205M and 1.358M accreting hydrogen rich material at 10–10 M yr–1. It is found that ignition of this material occurs at densities in excess of about 104 gm cm–3 and that the critical accumulated mass required to initiate the runaway is 0.7(1.5)×10–4 M for a 1.358(1.205)M white dwarf.  相似文献   

19.
In the region of the formation of weak and medium-strong lines, the microturbulence increases with height (V ver=0.7–0.9 km s-1, V hor= 1.1–1.5 km s-1), the macroturbulence decreases (V ver=1.6–1.4 km s-1, V hor= 2.4–1.5 km s-1), and the total velocity field (vertical component) is depth-independent (1.7 km s-1). The empirical damping constants for Fe, Ti, Cr, Ni lines are equal 1.36, 1.76, 1.66, 1.66, respectively. The correlation length (the Kubo-Anderson process has been used) in the solar photosphere is 520–550 km.  相似文献   

20.
In this paper we adopt the method of relativistic fluid dynamics to examine the number density distribution of stars around a massive black hole in the core of stellar clusters. We obtain extensive results,n(r) r –a, 3/2a9/2, which include, respectively, then(r) r –7/4 power law obtained by Bahcall and Wolf and then(r) r –9/4 power law by Peebles. Sincen(r) is not an observable quantity for star clusters, we also consider general relativity effects, i.e., the consequence of the bending of light, in calculating the projected density of stars in such a system. As an example we employ a massive black hole 103 M inlaid in the center of a globular cluster and calculate various projected densities of stars. The results show that cusp construction occurs in all cases unless the central black hole massM=0, and the polytropic index does not affect at all the position of the capture radiusr a. The obvious differences in the surface density is only embodied in the interior of the capture radius. At the outer regions of the core, the surface density of stars declines rapidly with ar –5 power law in all cases. These results can be applied to cases of unequal-mass and non-steady state.  相似文献   

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