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1.
The eclipse observations were performed at the Laboratory of Radio Astronomy of the CrAO in Katsiveli with stationary instrumentation of the Solar Patrol at wavelengths of 10.5 and 12.0 cm. The data obtained were used to determine the brightness temperature of the undisturbed Sun at solar activity minimum between 11-year cycles 23 and 24: T d10.5 = (43.7 ± 0.5) × 103 K at 10.5 cm and T d12.0 = (51.8 ± 0.5) × 103 K at 12.0 cm. The radio brightness distribution above the limb group of sunspots NOAA 0866 was calculated. It shows that at both wavelengths the source consisted of a compact bright nucleus about 50 × 103 km in size with temperatures T b10.5 = 0.94 × 106 K and T b12.0 = 2.15 × 106 K located, respectively, at heights h 10.5 = 33.5 × 103 km and h 12.0 = 43.3 × 103 km above the sunspot and an extended halo with a temperature T b = (230–300) × 103 K stretching to a height of 157 × 103 km above the photosphere. The revealed spatial structure of the local source is consistent with the universally accepted assumption that the radiation from the bright part of the source is generated by electrons in the sunspot magnetic fields at the second-third cyclotron frequency harmonics and that the halo is the bremsstrahlung of thermal electrons in the coronal condensation forming an active region. According to the eclipse results, the electron density near the upper boundary of the condensation was N e ≈ 2.3 × 108 cm?3, while the optical depth was τ ≈ 0.1 at an electron temperature T e ≈ 106 K. Thus, the observations of the March 29, 2006 eclipse have allowed the height of the coronal condensation at solar activity minimum to be experimentally determined and the physical parameters of the plasma near its upper boundary to be estimated.  相似文献   

2.
Observations of the solar eclipse on March 29, 2006, at the Laboratory of Radio Astronomy of the CrAO showed that the radio radius of the Sun at a wavelength of 1 m in the direction of the first contact was R d = 1.12 R ⊙ during solar activity minimum between cycles 23 and 24. The brightness temperature of the undisturbed Sun was T d = (0.6 ± 0.06) × 106 K. There was a noise storm source above the sunspot group NOAA 0865 whose bright nucleus had a size of 1′.3 and a brightness temperature T b = 16 × 106 K. The noise storm bursts were emitted from the region of the bright nucleus above the group NOAA 0865 and were absent during its covering by the disk of the Moon. Thermal radiation from a coronal condensation with a brightness temperature of (1?2) × 106 K extending out from the visible solar disk to 2′.7 was observed during the eclipse above the eastern limb sunspot group NOAA 0866. The bright nucleus in this limb source appeared 42 min after eclipse termination and persisted in the ensuing days. This may be indicative of the time of its emergence from behind the radio horizon formed by regular refraction of radio waves in the corona. The refractive displacement was measured by comparison with the eclipse observations at a shorter wavelength of 12 cm. Its value of 0′.96 is close to the calculated value of 0′.8.  相似文献   

3.
We observed Saturn at far-infrared and submillimeter wavelengths during the Earth's March 1980 passage through the plane of Saturn's rings. Comparison with earlier spectroscopic observations by D. B. Ward [Icarus32, 437–442 (1977)], obtained at a time when the tilt angle of the rings was 21.8°, permits separation of the disk and ring contributions to the flux observed in this wavelength range. We present two main results: (1) The observed emission of the disk between 60 and 180 μm corresponds to a brightness temperature of 104 ± 2°K; (2) the brightness temperature of the rings drops approximately 20°K between 60 and 80 μm. Our data, in conjunction with the data obtained by other observers between 1 μm and 1 mm, permit us to derive an improved estimate for the total Saturnian surface brightness of (4.84 ± 0.32) × 10?4W cm?2 corresponding to an effective temperature of 96.1 ± 1.6°K. The ratio of radiated to incident power, PR/PI, is (1.46 ± 0.08)/(1 - A), where A is the Bond albedo. For A = 0.337 ± 0.029, PR/PI = 2.20 ± 0.15 and Saturn's intrinsic luminosity is LS = (2.9 ± 0.5) × 10?10L⊙.  相似文献   

4.
Solar radio fluxes, Zurich relative sunspot number Rz, and Solar Call plage indexes daily values for the period 1957–1980 are analyzed in order to test the stability of the series with respect to time and solar activity. It is found that between the series of the 3,8 and 10 cm radio fluxes and the series of Rz no significant trend with time, solar activity or solar cycle exists when mean values for periods of the order of one year are considered.Then, the daily solar u.v.-irradiances measured since 1969 for H-Lyman-alpha and-beta, the Hel-resonance line and HeII-Lyman-alpha are compared with the 10.7 cm radio fluxes and adjusted. After adjustment, the behaviour of the four series of irradiances with respect to the 10.7 cm flux shows a similar structure as the behaviour typical for the series of the 3 cm or the 8 cm fluxes.This adjustment allows the determination of the slope of the mean variation of the u.v.-irradiances with solar activity. The increases from solar minimum to solar maximum related to the minimum values are respectively : 60% for H-Lyman-alpha, 80% for H-Lyman-beta and 90% for Hel and Hell.  相似文献   

5.
The analysis of observations of the eclipse on August 1, 2008, at wavelengths of 10.5 and 12 cm demonstrated that, in the epoch of deep minimum between the 23rd and 24th cycles of solar activity, the radio radius of the solar disk in the equatorial direction was 120 × 103 km larger than the radio radius in the polar direction. In this case, the brightness temperature of the polar region turned out to be of the order of (35–37) × 103 K and corresponded to the radiation emission from upper layers of the chromosphere from an altitude of about 11 × 103 km. At the heliolatitude <25° beyond the visible disk at a distance of about 70 × 103 km from the photosphere an increased radio brightness of up to 100 × 103 K was observed, which testifies to the increased electron density in the equatorial zone of the corona at the complete absence of groups of spots on the solar disk.  相似文献   

6.
The transport of energy in space plasmas, especially in the solar wind, is far from being understood. Measuring the temperature of the electrons and their non-thermal properties is essential to understand the transport properties in collisionless plasmas. Quasi-thermal noise spectroscopy is a reliable tool for measuring the electron temperature accurately since it is less sensitive to the spacecraft perturbations than particle detectors. We apply this method to Ulysses radio data obtained during the first pole-to-pole fast latitude scan in the high-speed solar wind, using a kappa function to describe the electron velocity distribution. We deduce the variations with heliocentric distance between 1.5 and 2.3 AU in the fast solar wind at high latitude in terms of three fitting parameters: the electron density varies as n e??R ?1.96±0.08, the electron temperature as T e??R ?0.53±0.15, and the kappa index of the distribution remains constant at ??=2.0±0.2. These observations agree with the predictions of the exospheric theory.  相似文献   

7.
《Icarus》1987,71(1):159-177
Observations of Mars at wavelengths of 2 and 6 cm were made using the VLA in its A configuration. The season on Mars was late spring in the Northern Hemisphere (Ls = 60°). The sub-Earth latitude was 25°N, so the geometry for viewing the north polar region was optimal. Whole-disk brightness temperatures were estimated to be 193.2 ± 1.0°K at 2 cm and 191.2 ± 0.6°K at 6 cm (formal errors only). Since measurements of the polarized flux were taken at the same time, whole-disk effective dielectric constants could be estimated and from these estimates of subsurface densities could be made. The results of these calculations yielded a whole-disk effective dielectric constant of 2.34 ± 0.05, which implied a subsurface density of 1.24 ± 0.11 g cm−3 at 2 cm. The same calculations at 6 cm yielded an effective density of 1.45 ± 0.10 g cm−3 and dielectric constant of 2.70 ± 0.10. From the mapped data these parameters were also estimated as a function of latitude between latitudes of 15°S and 60°N. In addition to the effective dielectric constant and subsurface density, the radio absorption length of the subsurface was estimated. The radio absorption length for most of these latitudes was about 15 wavelengths with formal errors on the order of 5 or 10 wavelengths. The estimation of the effective dielectric constant at most latitudes was between 2 and 3.5 with only slight differences between the two different wavelengths. These estimates of the dielectric constant lead to estimation of the subsurface densities as a function of latitude. Most calculations of the subsurface density yielded results between 1 and 2 g cm−3 with errors on the order of 0.5 g cm−3. These results seem to imply that the subsurface is not much different than the surface as observed by the Viking and Mariner missions. In line with this, a comparison of the correlation of the dielectric constant at each wavelength with the thermal inertia determined from infrared measurements of the surface temperature shows that the correlation at 2 cm is slightly stronger than the correlation at 6 cm. Since the 2-cm radiation comes from a region closer to the surface than the 6-cm radiation, this decrease in correlation with depth is consistent with the idea that the physical makeup of the subsurface is varying slowly in the near subsurface region.  相似文献   

8.
An Estimate for the Size of Sunspot Cycle 24   总被引：1，自引：0，他引：1  
R. P. Kane 《Solar physics》2013,282(1):87-90
For the sunspot cycles in the modern era (cycle?10 to the present), the ratio of R Z(max)/R Z(36th month) equals 1.26±0.22, where R Z(max) is the maximum amplitude of the sunspot cycle?using smoothed monthly mean sunspot number and R Z(36th month) is the smoothed monthly mean sunspot number 36 months after cycle?minimum. For the current sunspot cycle?24, the 36th month following the cycle?minimum occurred in November 2011, measuring?61.1. Hence, cycle?24 likely will have a maximum amplitude of about 77.0±13.4 (the one-sigma prediction interval), a value well below the average R Z(max) for the modern era sunspot cycles (about 119.7±39.5).  相似文献   

9.
Bird  M. K.  Janardhan  P.  Wilson  T. L.  Huchtmeier  W. K.  Gensheimer  P.  Lemme  C. 《Earth, Moon, and Planets》1997,78(1-3):21-28
K-band radio observations of comet Hale-Bopp (C/1995 O1) were conducted in March/April 1997 at the 100-m Telescope of the Max-Planck-Institut für Radioastronomie. Emission was firmly detected from the five lowest metastable (J = K)inversion transitions of ammonia. Assuming a thermal distribution for the metastable states of NH3, we derive a rotational temperature of 104 ± 30 K and an ammonia production rate at perihelion of6.6 ± 1.3 × 1028 s-1.The updated ammonia-to-water abundance ratio is found to be of the order of 1.0%. We also report a marginal detection of the 616–523transition line of water at λ = 1.35 cm. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

10.
Two coherently related radio signals transmitted from Voyager 1 at wavelengths of 13 cm (S-band) and 3.6 cm (X-band) were used to probe the equatorial atmosphere of Titan. The measurements were conducted during the occultation of the spacecraft by the satellite on November 12, 1980. An analysis of the differential dispersive frequency measurements did not reveal any ionization layers in the upper atmosphere of Titan. The resolution was approximately 3 × 103 and 5 × 103 electrons/cm3 near the evening and morning terminators, respectively. Abrupt signal changes observed at ingress and egress indicated a surface radius of 2575.0 ± 0.5 km, leading to a mean density of 1.881 ± 0.002 g cm?3 for the satellite. The nondispersive data were used to derive profiles in height of the gas refractivity and microwave absorption in Titan's troposphere and stratosphere. No absorption was detected; the resolution was about 0.01 dB/km at the 13-cm wavelength. The gas refractivity data, which extend from the surface to about 200 km altitude, were interpreted in two different ways. In the first, it is assumed that N2 makes up essentially all of the atmosphere, but with very small amounts of CH4 and other hydrocarbons also present. This approach yielded a temperature and pressure at the surface of 94.0 ± 0.7°K and 1496 ± 20 mbar, respectively. The tropopause, which was detected near 42 km altitude, had a temperature of 71.4 ± 0.5°K and a pressure of about 130 mbar. Above the tropopause, the temperature increased with height, reaching 170 ± 15°K near the 200-km level. The maximum temperature lapse rate observed near the surface (1.38 ± 0.10°K/km) corresponds to the adiabatic value expected for a dry N2 atmosphere—indicating that methane saturation did not occur in tbis region. Above the 3.5-km altitude level the lapse rate dropped abruptly to 0.9 ± 0.1°K/km and then decreased slowly with increasing altitude, crossing zero at the tropopause. For the N2 atmospheric model, the lapse rate transition at the 3.5-km level appears to mark the boundary between a convective region near the surface having the dry adiabatic lapse rate, and a higher stable region in radiative equilibrium. In the second interpretation of the refractivity data, it is assumed, instead, that the 3.5 km altitude level corresponds to the bottom of a CH4 cloud layer, and that N2 and CH4 are perfectly mixed below this level. These assumptions lead to an atmospheric model which below the clouds contains about 10% CH4 by number density. The temperature near the surface is about 95°K. Arguments concerning the temperature lapse rates computed from the radio measurements appear to favor models in which methane forms at most a limited haze layer high in the troposphere.  相似文献   

11.
Open star clusters from the MWSC (Milky Way Star Clusters) catalogue have been used to determine the Galactic rotation parameters. The circular rotation velocity of the solar neighborhood around the Galactic center has been found from data on more than 2000 clusters of various ages to be V 0 = 236 ± 6 km s?1 for the adopted Galactocentric distance of the Sun R 0 = 8.3 ± 0.2 kpc. The derived angular velocity parameters are Ω 0 = 28.48 ± 0.36 km s?1 kpc?1, Ω’0 = ?3.50 ± 0.08 km s?1 kpc?2, and Ω″0 = 0.331 ± 0.037 km s?1 kpc?3. The influence of the spiral density wave has been detected only in the sample of clusters younger than 50 Myr. For these clusters the amplitudes of the tangential and radial velocity perturbations are f θ = 5.6 ± 1.6 km s?1 and f R = 7.7 ± 1.4 km s?1, respectively; the perturbation wavelengths are λ θ = 2.6 ± 0.5 kpc (i θ = ?11? ± 2?) and λ R = 2.1 ± 0.5 kpc (i R = ?9? ± 2?) for the adopted four-armed model (m = 4). The Sun’s phase in the spiral density wave is (χ⊙)θ = ?62? ± 9? and (χ⊙)R = ?85? ± 10? from the residual tangential and radial velocities, respectively.  相似文献   

12.
Additional analysis of the behavior of the international sunspot number (R) series and the solar radio flux density (F10.7 cm) series during two long (250–500 days) and distinct episodes of persistent ≈13-day variations (Crane, Solar Phys. 1998, 253, 177) is reported. The conclusion is that while the center-to-limb behavior of R does not change between solar minimum and solar maximum, F10.7 cm exhibits significantly less limb brightening at solar maximum than at solar minimum.  相似文献   

13.
We discuss observations of the Moon at a wavelength of 49.3 cm made with the Owens Valley Radio Observatory Interferometer. These observations have been fit to models in order to estimate the lunar dielectric constant, the equatorial subsurface temperature, the latitude dependence of the subsurface temperature, and the subsurface temperature gradient. The models are most consistent with a dielectric constant of 2.52 ± 0.01 (formal errors), an equatorial subsurface temperature of 249?5+8K, and a change in the subsurface temperature with latitude (ψ), which is proportional to cos0.38ψ. Since the temperature of the Moon has been measured by the Apollo Lunar Heat Flow Experiment, we have been able to use our determination of the equatorial temperature to estimate the error in the flux density calibration scale at 49.3cm (608 MHz). This results in a correction factor of 1.03 ± 0.04, which must be applied to the flux density scale. This factor is much different from 1.21 ± 0.09 estimated by Muhleman et al. (1973) from the brightness temperature of Venus and apparently indicates that the observed decrease in the brightness temperature of Venus at long wavelengths is a real effect.The estimates of the temperature gradient, which are based on the measurement of limb darkening, are small and negative (temperature decreases with depth) and may be insignificantly different from zero since they are only as large as their formal errors. We estimate that a temperature gradient in excess of 0.6K/m at 10m depth would have been observed. Thus, a temperature gradient like that measured in situ at the Apollo 15 and 17 landing sites in the upper 2m of the regolith is not typical of the entire lunar frontside at the 10m depths where the 49.3 cm wavelength emission originates. This result may indicate that the mean lunar heat flow is lower than that measured at the Apollo landing sites, that the thermal conductivity is greater at 10m depth than it is at 2m depth, or that the radio opacity is greater at 10m depth than at 2m depth. The negative estimates of the temperature gradient indicate that the Moon appeared limb bright and might be explained by scattering of the emission from boulders or an interface with solid rock. The presence of solid rock at 10m depths will probably cause heat flows like those measured by Apollo to be unobservable by our interferometric method at long wavelengths, since it will cause both the thermal conductivity and radio opacity of the regolith to increase. Thus, our data may be most consistent with a change in the physical properties of the regolith to those of solid rock or a mixture of rock and soil at depths of 7 to 16m. Our results show that future radio measurements for heat flow determinations must utilize wavelengths considerably shorter than 50 cm (25 cm or less) to avoid the rock regions below the regolith.  相似文献   

14.
We have redetermined the kinematic parameters of the Gould Belt using currently available data on the motion of nearby young (log t < 7.91) open clusters, OB associations, and moving stellar groups. Our modeling shows that the residual velocities reach their maximum values of ?4 km s?1 for rotation (in the direction of Galactic rotation) and +4 km s?1 for expansion at a distance from the kinematic center of ≈300 pc. We have taken the following parameters of the Gould Belt center: R 0 = 150 pc and l 0 = 128°. The whole structure is shown to move relative to the local standard of rest at a velocity of 10.7 ± 0.7 km s?1 in the direction l = 274° ± 4° and b = ?1° ± 3°. Using the derived rotation velocity, we have estimated the virial mass of the Gould Belt to be 1.5 × 106 M ⊙.  相似文献   

15.
We have selected and analyzed a sample of OB stars with known line-of-sight velocities determined through ground-based observations and with trigonometric parallaxes and propermotions from the Gaia DR2 catalogue. Some of the stars in our sample have distance estimates made from calcium lines. A direct comparison with the trigonometric distance scale has shown that the calcium distance scale should be reduced by 13%. The following parameters of the Galactic rotation curve have been determined from 495 OB stars with relative parallax errors less than 30%: (U, V,W)⊙ = (8.16, 11.19, 8.55)± (0.48, 0.56, 0.48) km s?1, Ω0 = 28.92 ± 0.39 km s?1 kpc?1, Ω'0 = ?4.087 ± 0.083 km s?1 kpc?2, and Ω″ 0 = 0.703 ± 0.067 km s?1 kpc?3, where the circular velocity of the local standard of rest is V0 = 231 ± 5 km s?1 (for the adopted R0 = 8.0 ± 0.15 kpc). The parameters of the Galactic spiral density wave have been found from the series of radial, VR, residual tangential, ΔVcirc, and vertical, W, velocities of OB stars by applying a periodogram analysis. The amplitudes of the radial, tangential, and vertical velocity perturbations are fR = 7.1± 0.3 km s?1, fθ = 6.5 ± 0.4 km s?1, and fW = 4.8± 0.8 km s?1, respectively; the perturbation wavelengths are λR = 3.3 ± 0.1 kpc, λθ = 2.3 ± 0.2 kpc, and λW = 2.6 ± 0.5 kpc; and the Sun’s radial phase in the spiral density wave is (χ⊙)R = ?135? ± 5?, (χ⊙)θ = ?123? ± 8?, and (χ⊙)W = ?132? ± 21? for the adopted four-armed spiral pattern.  相似文献   

16.
The results of JHKLM photometry for Nova Delphini 2013 obtained in the first sixty days after its outburst are analyzed. Analysis of the energy distribution in a wide spectral range (0.36–5 µm) has shown that the source mimics the emission of normal supergiants of spectral types B5 and A0 for two dates near its optical brightness maximum, August 15.94 UT and August 16.86 UT, respectively. The distance to the nova has been estimated to be D ≈ 3 kpc. For these dates, the following parameters have been estimated: the source’s bolometric fluxes ～9 × 10?7 and ～7.2 × 10?7 erg s?1 cm?2, luminosities L ≈ 2.5 × 105 L ⊙ and ≈2 × 105 L ⊙, and radii R ≈ 6.3 × 1012 and ≈1.2 × 1013 cm. The nova’s expansion velocity near its optical brightness maximum was ～700 km s?1. An infrared (IR) excess associated with the formation of a dust shell is shown to have appeared in the energy distribution one month after the optical brightness maximum. The parameters of the dust component have been estimated for two dates of observations, JD2456557.28 (September 21, 2013) and JD2456577.18 (October 11, 2013). For these dates, the dust shell parameters have been estimated: the color temperatures ≈1500 and ≈1200 K, radii ≈6.5 × 1013 and 1.7 × 1014 cm, luminosities ～4 × 103 L ⊙ and ～1.1 × 104 L ⊙, and the dust mass ～1.6 × 1024 and ～1025 g. The total mass of the material ejected in twenty days (gas + dust) could reach ～1.1 × 10?6 M ⊙. The rate of dust supply to the nova shell was ～8 × 10?8 M ⊙ yr?1. The expansion velocity of the dust shell was about 600 km s?1.  相似文献   

17.
F.H. Briggs  B.H. Andrew 《Icarus》1980,41(2):269-277
We present high-resolution interferometry of Uranus at 6 cm wavelength and single-dish observations of the disk-averaged brightness temperature, TB, at 2.8 and 4.8 cm wavelength. The 1978 measurements of TB of 228 ± 2,243 ± 9, and 259 ± 4 K at 2.8, 4.8, and 6 cm, respectively, support the finding of M. J. Klein and J. A. Turegano (1978, Astrophy. J.224, L31–L34) that the brightness temperature of Uranus has been rising. There is no evidence for radio emission from outside the visible disk at 6 cm. Radiation from a synchrotron radiation belt or from the Uranian rings is certainly less than 10% of the total radio flux. The interferometry shows a possible 55 ± 20 K difference in brightness temperature between the equator and the currently exposed pole. The pole appears to be ～275 K while the equator is ～220 K. However, a permanent gradient of this magnitude is insufficient to account for the rise in disk-averaged brightness by simple reorientation of Uranus' globe relative to our line of sight. The changing insolation probably triggers a redistribution of the trace constituent NH3 which is responsible for the radio opacity. The NH3 may be interacting strongly with H2S on Uranus.  相似文献   

18.
The observations of the solar radio emission on September 11, 2001, with the RATAN-600 radio telescope (southern sector) at four centimeter wavelengths (1.92, 2.24, 2.74, and 3.21 cm) revealed synchronous brightenings in solar radio sources. These were identified on the solar photosphere with active regions that were spaced up to ～106 km apart (AR 9608 and AR 9616). We discuss manifestations of the possible mechanisms of synchronous brightenings in solar sources in a narrow microwave spectral band. The significant linear correlation (ρc = 0.84–0.92) between the relative fluxes of AR 9610 and AR 9608 at 1.92 and 2.24 cm and the significant linear correlation (ρc = 0.65–0.84) between the relative fluxes of AR 9606 and AR 9608 at 3.21 cm in a two-hour interval of observations are indicative of the interconnection between these active regions not only during flares and bursts, but also in the periods of their absence. This confirms the existence of a large-scale temporal component in the dynamics of the radio flux variations for these active regions. We found a difference between the temporal variations of the radio emission from the halo and the solar radio sources under consideration. The times of increase in the total solar soft X-ray (0.5–4.0 Å, 1.0–8.0 Å; GOES 8, GOES 10) flux are shown to coincide with the times of increase in the fluxes from the solar radio sources at short centimeter wavelengths.  相似文献   

19.
The neutral hydrogen emission at 21 cm has been investigated with the RATAN-600 radio telescope in the vicinity of the supernova remnant HB9. A clumpyHI shell with radial motions surrounding the remnant has been detected. Its measured parameters contradict the connection with a shock wave from a supernova explosion. The shell formation under the action of a wind from a star that exploded as a supernova at the end of its evolution seems more realistic. The characteristics of the star obtained from the observed shell parameters are the following: a wind power of 0.5 × 1038 erg s?1, a mass-loss rate of 3.7 × 10?5 M ⊙ yr?1, and an age of 3 × 106 yr. Given the measurement errors, the mass of the star is estimated to be >8M ⊙.  相似文献   

20.
Three three-component (bulge, disk, halo) model Galactic gravitational potentials differing by the expression for the dark matter halo are considered. The central (bulge) and disk components are described by the Miyamoto–Nagai expressions. The Allen–Santillán (I), Wilkinson–Evans (II), and Navarro–Frenk–White (III) models are used to describe the halo. A set of present-day observational data in the range of Galactocentric distances R from 0 to 200 kpc is used to refine the parameters of thesemodels. For the Allen–Santillán model, a dimensionless coefficient γ has been included as a sought-for parameter for the first time. In the traditional and modified versions, γ = 2.0 and 6.3, respectively. Both versions are considered in this paper. The model rotation curves have been fitted to the observed velocities by taking into account the constraints on the local matter density ρ ⊙ = 0.1 M ⊙ pc?3 and the force K z =1.1/2πG = 77 M ⊙ pc?2 acting perpendicularly to the Galactic plane. The Galactic mass within a sphere of radius 50 kpc, M G (R ≤ 50 kpc) ≈ (0.41 ± 0.12) × 1012 M ⊙, is shown to satisfy all three models. The differences between the models become increasingly significant with increasing radius R. In model I, the Galactic mass within a sphere of radius 200 kpc at γ = 2.0 turns out to be greatest among the models considered, M G (R ≤ 200 kpc) = (1.45 ±0.30)× 1012 M ⊙, M G (R ≤ 200 kpc) = (1.29± 0.14)× 1012 M ⊙ at γ = 6.3, and the smallest value has been found in model II, M G (R ≤ 200 kpc) = (0.61 ± 0.12) × 1012 M ⊙. In our view, model III is the best one among those considered, because it ensures the smallest residual between the data and the constructed model rotation curve provided that the constraints on the local parameters hold with a high accuracy. Here, the Galactic mass is M G (R ≤ 200 kpc) = (0.75 ± 0.19) × 1012 M ⊙. A comparative analysis with the models by Irrgang et al. (2013), including those using the integration of orbits for the two globular clusters NGC 104 and NGC 1851 as an example, has been performed. The third model is shown to have subjected to a significant improvement.  相似文献   

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