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1.
Between 1994 and 2006, we obtained uniform spectroscopic observations of SS 433 in the region of Hα. We determined Doppler shifts of the moving emission lines, Hα + and Hα ?, and studied various irregularities in the profiles for the moving emission lines. The total number of Doppler shifts measured in these 13 years is 488 for Hα ? and 389 for Hα +. We have also used published data to study possible long-term variations of the SS 433 system, based on 755 Doppler shifts for Hα ? and 630 for Hα + obtained over 28 years. We have derived improved kinematic model parameters for the precessing relativistic jets of S S 433 using five-and eight-parameter models. On average, the precession period was stable during the 28 years of observations (60 precession cycles), at 162.250d ± 0.003d. Phase jumps of the precession period and random variations of its length with amplitudes of ≈6% and ≈1%, respectively, were observed, but no secular changes in the precession period were detected. The nutation period, P nut = 6.2876d ± 0.00035d, and its phase were stable during 28 years (more than 1600 nutation cycles). We find no secular variations of the nutation cycle. The ejection speed of the relativistic jets, v, was, on average, constant during the 28 years, β = v/c = 0.2561 ± 0.0157. No secular variation of β is detected. In general, S S 433 demonstrates remarkably stable long-term characteristics of its precession and nutation, as well as of the central “engine” near the relativistic object that collimates the plasma in the jets and accelerates it to v = 0.2561c. Our results support a model with a “slaved” accretion disk in S S 433, which follows the precession of the optical star’s rotation axis.  相似文献   

2.
We estimate the absolute intensity of the Hα emission line in M17 based on spectroscopic observations with the 70 cm telescope of the Fesenkov Astrophysical Institute and the 1.25 m telescope of the Sternberg Astronomical Institute’s Crimean Laboratory. The visual extinction, A v , is derived for about 250 regions in the nebula via a comparison of the optical (Hα) and radio (21 cm continuum) emissions. The A v values for the eastern, optically bright, part of the nebula are 2–6m. For the western part, which is covered by a dark cloud, the extinction is A v = 7?14.5m. We derived I(Hα)/I([NII] λ6584) ratios and estimated the degree of ionization of nitrogen in the nebula; we find that most nitrogen is in the [NIII] state.  相似文献   

3.
The results of long-term monitoring of the quasar 3C 273 at wavelengths from radio to gamma rays between 1963 and 2011 are presented. The variations of the source flux density are studied using harmonic and wavelet analysis techniques. The values and frequency-time localizations of harmonic components in the flux-density variations are determined. The eight-year radio-variability period reported earlier had become gradually reduced and attenuated by 2000. The optical light curve has a component with a quasi-period of approximately 13 years. Cyclic variations whose periodicity gradually increased from approximately one to two years were observed in the X-ray between 1996 and 2006. The relative time delays between the light curves at different radio frequences are determined. The frequency dependence of time delays is approximated by the power law, ΔT(ν) ∝ ν ?1/k with k = 1.4 ± 0.1, which can be used to infer the corresponding core shift and estimate the core-region magnetic field as B 1 pc = 0.5 ± 0.1 G. This approach is preferable to other methods, since it does not require multi-frequency VLBI observations and is a simple and effective tool for studying Active Galactic Nuclei.  相似文献   

4.
Our measurements of the arrival-time delays of radio pulses from the Crab pulsar, PSR B0531+21, at low frequencies 111, 63, and 44 MHz revealed additional delays compared to the usual quadratic frequency relation, Δt(v) ∝ v ?2. These additional delays are 65 ms between 63 MHz and 111 MHz—i.e., a factor of two longer than the pulsar’s period, i.e., a factor of five longer than the pulsar period—and cannot be explained by the “twisting” of the magnetic-field lines by the rotation of the pulsar. We suggest the model in which a previously unknown high-density plasma layer with a high electron concentration is present along the line of sight in the Crab nebula, causing an additional frequency-dependent delay of the observed radio pulses at low frequencies due to the contribution of the n e 2 v ?4 term in the dispersion-delay formula. The parameters of this inferred layer have been derived: emission measure EM ? 4 × 106 pc/cm6, electron density n e ? 106 cm?3, depth along the line of sight d ? 4 × 10?6 pc, and electron temperature T e ≥ 2 × 106 K.  相似文献   

5.
The mean 1983–1996 UBV light curves of the dwarf nova SS Cyg are used to derive the binary parameters in the quiescent state. Solutions are obtained for a classical hot-spot model and a model with an energy source lying outside the accretion disk. Photometric and spectroscopic data are combined to infer the masses and radii of the binary components. The white dwarf in SS Cyg is one and a half times as massive as the red dwarf, q=M wd /M rd ～1.45, M rd ～0.46M ⊙ and M wd ～0.66M ⊙. The orbital inclination of the system is i?51°–54°. The contribution of the accretion disk to the total flux in the quiescent state is estimated to be ～47–49% and ～54% in the VU and B filters, respectively. The hot spot contributes less than ～3% to the total optical flux. In the “non-classical” hot-spot model, the disk and bulge contributions are 27 and 2–8%, respectively, depending on the orbital phase. The shape of the mean light curves of SS Cyg suggests asymmetric heating of the red-dwarf surface in the quiescent state by high-temperature radiation generated in the hot-spot region.  相似文献   

6.
Spectroscopic monitoring of SS 433 was performed during the 11 years between 2007 and 2017. Shifts of the moving Hα emission lines are analyzed and corresponding radial velocity curves plotted. All published spectroscopic data on SS 433 are used to search for secular variations of the parameters of the kinematic model. Deviations of the model parameters from their mean values are observed during relatively short time intervals (several years), but no secular changes have been detected. The presence of a component varying periodically with the orbital period is confirmed for the velocity variations for the matter in the relativistic jets, possibly indicating that the orbit of SS 433 is slightly elliptical. The stability of the parameters of the kinematic model testifies that a model with a slaved accretion disk that follows the precession of the optical star’s rotation axis is very suitable for the supercritical accretion disk in the SS 433 system.  相似文献   

7.
A method is proposed for estimating the distances to extragalactic radio sources using spec-troscopic data on the sizes of the broad-line regions of quasars and radio galaxies R BL and VLBI data on the transverse angular sizes of the radio jets emerging from their nuclei (θ θ j ). This approach is based on the fact that observational data on the transverse linear sizes of radio jets (l θ j ) associated with the nearest radio sources and theoretical concepts about the formation of radio jets in the central regions of a magnetized accretion disk suggest that (l θ j ) and R BL should be approximately equal.  相似文献   

8.
The structure of the ejector region in the active star-forming region Orion KL has been studied over a broad dynamic range with a high angular resolution of 0.1 milliarcsec, or 0.05 AU. The line profile of the H2O supermaser emission has broad wings and can be represented as a superposition of two Gaussians with frequency widths Δf1=31 kHz and Δf2=163 kHz. The line intensities are I1≈3×105 Jy/beam and I2≈400 Jy/beam, and the brightness temperatures, Tb1≈5×1016 K and Tb2≈6×1014 K. The broadband ejector emission is determined by a rotating bipolar outflow with a rotational period of 5 months. The ejector emission in the 31-kHz component at a velocity of 7.64 km/s is amplified by more than two orders of magnitude by the surrounding envelope. The maser amplification regime is partially saturated.  相似文献   

9.
We discuss the results of deep surveys of a ±10′ strip of the sky, centered on the declination of SS 433, carried out on the Northern sector of the RATAN-600 telescope at 2.7 and 7.6 cm in 1987–2000. The survey objects are cross-identified with sources in the NVSS catalog and the corresponding two-frequency spectral indices determined. We find a decrease in the mean spectral index in the transition from objects with flux densities S 21 ≥ 30 mJy to those with 15 < S 21 < 30 mJy. The constructed log N — logS relation at 2.7 cm has a slope of 3/2 at flux densities ≥300 mJy and flattens at weaker flux densities. The 1.4 GHz (NVSS), 3.94 GHz (RATAN-600), and 11.11 GHz (RATAN-600) data are used to estimate the number of objects per square degree at a wavelength of 1 cm.  相似文献   

10.
Results of a study of a strong flare of H2O maser emission in the star-forming region Sgr B2(M) in 2004 are reported. The observations were carried out on the 22-m radio telescope of the Pushchino Radio Astronomy Observatory. The main emission, with its flux density reaching 3800 Jy, was concentrated in a narrow radial-velocity interval (about 3 km/s) and was most likely associated with the compact group r, while the emission at VLSR > 64 km/s came from group q. After 1994, the variations of the H2O maser emission in Sgr B2(M) became cyclic with a mean period of 3 years.  相似文献   

11.
The detection of pulsed radio emission from the recently discovered X-ray pulsar J0205+6449 in the young supernova remnant 3C 58 is reported together with the results of first studies of this emission. The observations were carried out at 111 and 88 MHz on radio telescopes of the Pushchino Observatory. The pulsar period, 65.68 ms, and period derivative, \(\dot P = 1.9 \times 10^{ - 13} \), have been confirmed. The integrated pulse profile at 111 MHz has been obtained and the flux density and spectral index α=2.8 measured. The pulsar dispersion measure DM=141 pc cm?3 has been confirmed. This dispersion measure yields a distance to the pulsar of d=6.4 kpc, a factor of two or more greater than the previously favored distance to the supernova remnant 3C 58 (2.6 kpc). The problem of the age and distance of the pulsar-SNR system is discussed. If the age of the pulsar J0205+6449 is equal to that of the SNR (820 years), this pulsar is the youngest known radio pulsar. The synchrotron mechanism for the radio and X-ray emission is proposed to explain the lower radio and X-ray luminosity of this new pulsar compared to the Crab pulsar, which is similar to it in many ways. Optical emission with luminosity Lopt=1031 erg/s and gamma-ray emission with Lγ=7×1035 erg/s are predicted, and the steep radio spectrum (α≈3) can be explained.  相似文献   

12.
Observations of circumstellar maser emission from the long-period variable R Cas in the 1.35-cm water-vapor line are reported. The observations were carried out on the 22-m radio telescope of the Pushchino Radio Astronomy Observatory in 1980–2003 (JD=2444409–2452724). Over the 23 years of observations, strong flares in the H2O line profile were recorded in 1982 (with a peak flux density up to 400 Jy) and 1986–1989 (up to 750 Jy). Subsequently, from 1990 to March 2003, the H2O line flux was usually below the detection threshold of the radio telescope (<5–10 Jy). Episodic small increases of the emission with peak flux densities of 20–60 Jy were observed. The variations of the H2O line flux F are correlated with variations in the visual brightness of the star. The phase delay Δγ of the F variations relative to the optical light curve of R Cas ranged from 0.2–0.3P during the observations (P=430.46d is the star's period). A model for the variability of the H2O maser in R Cas is discussed. If the variations are due to periodic impacts by shock waves driven by the stellar pulsations, the time for the shock to travel from the photosphere to the inner boundary of the H2O-masing shell may reach 2–4P. The flares could be due to transient episodes of enhanced mass loss by the star or to the propagation of an exceptionally strong shock from the stellar surface.  相似文献   

13.
The integrated radio luminosities of 311 long-period (P > 0.1 s) and 27 short-period (P < 0.1 s) pulsars have been calculated using a new compilation of radio spectra. The luminosities are in the range 1027 ? 1030 erg/s for 88% of the long-period pulsars and 1028 ? 1031 erg/s for 88% of the short-period pulsars. We find a high correlation between the luminosity L and the estimate L 1 = S 400 d 2 from the catalog of Taylor et al. The factor η for the transformation of the rotational energy of the neutron star into radio emission increases-decreases with increasing period for long-period and short-period pulsars. The mean value of η is ?3.73 for the long-period and ?4.85 for short-period pulsars. No dependence was found between L and the pulsar’s kinematic age t k = |z|/〈v z〉, where |z| and 〈v z〉 = 300 km/s are the pulsars’ height above the plane of the Galaxy and mean velocity. A dependence of L on the rate of rotational energy losses ? was found for both groups of pulsars. It is shown that L ∝ ? 1/3 for the entire sample. The pulsar luminosity function is constructed, and the total number and birth rate of pulsars in the Galaxy are calculated.  相似文献   

14.
Long-term measurements of the radio flux density of the young supernova remnant Cassiopeia A relative to the radio galaxy Cygnus A have been carried out at 290 and 927 MHz. We have obtained for the mean rates of the secular decrease of the radio emission of Cassiopeia A d 290 MHz = ?0.67 ± 0.04% year?1 for 1978–2005 and d 927 MHz = ?0.71 ± 0.035% year?1 for 1977–2004. The evolution of the radio spectrum of Cassiopeia A is traced based on long-term observations at 38, 151.5, 290, 927, and 2924 MHz.  相似文献   

15.
Spectroscopic and photometric data for the two rapidly rotating members of the α Persei cluster He 373 and AP 225 are analyzed. Improved estimates have been obtained for the projected equatorial rotation velocities: v sin i = 164 km/s for He 323 and v sin i = 129 km/s for AP 225. Multi-band photometric mapping is used to map the spot distributions on the surfaces of the two stars. The fractional spotted areas S and mean temperature difference ΔT between the unspotted photosphere and the spots are estimated (S = 7% and ΔT = 1000 K for He 373; S = 9% and ΔT = 800 K for AP 225). The H α line profiles of both stars have variable emission components whose widths are used to deduce the presence of extended regions of emission reaching the corotation radius.  相似文献   

16.
We compare U BV R photometry of CI Cam obtained using facilities at the Sternberg Astronomical Institute in 1998–2001 and medium-resolution spectroscopy obtained at the Special Astrophysical Observatory in the same period. The photometric measurements and fluxes in the Balmer and some Fe II emission lines in the post-outburst quiescent spectrum of CI Cam display cyclic variations with a period of 1100±50d. These variations could be due to orbital motion in a widely separated binary; one component, a giant, produces a reflection effect on the surface facing the other, compact component. Our V-band photometry confirms the \(11\mathop d\limits_. 7\) period found by Miroshnichenko before the outburst but shows a lower amplitude (3%). We investigate the possibility that this photometric period is the same as the rotational period of the radio jets measured using the VLA. Based on modeling of the radio map, we estimate the inclination of the jet rotation axis to the line of sight, i=35°–40°; the angle between the rotational axis and jet ejection direction, ?=7°–10°; and the jet spatial velocity, 0.23–0.26 c. The equivalent widths and fluxes of various spectral lines show different variation amplitudes during outburst and significantly different behavior during quiescence. We have detected five patterns of behavior, which provide evidence for stratification of the gas and dust envelope surrounding the system. The brightening of the [N II] forbidden line is delayed by 50–250d relative to the X-ray outburst maximum.  相似文献   

17.
Results of the observations of the blazar J1159+2914 (S1156+295) in 2010–2013 are reported. The observations were carried out on the RATAN-600 radio telescope (Special Astrophysical Observatory, Russian Academy of Sciences) at 4.85, 7.7, 11.1, and 21.7 GHz and the 32-m Zelenchuk and Badary radio telescopes of the Quasar-KVO Complex (Institute of Applied Astronomy, Russian Academy of Sciences) at 4.85 and 8.57 GHz. A flare peaked in August 2010, after which the flux density decreased monotonically at all studied frequencies. Variability on a timescale of 7 days was detected at 7.7 and 11.1 GHz near the flare maximum. The delay in the maximum at 7.7 GHz relative to the maximum at 11.1 GHz was 1.5 d, implying a Lorentz factor γ = 55 and angle of the jet to the line of sight θ ≈ 2° since mid-2011. Searches for intraday variability (IDV) were undertaken by the 32-m telescopes, mostly since mid-2011. Intraday variability was confidently detected only at the Badary station on November 10–11, 2012 at 4.85 GHz: the IDV timescale was τ acf = 6 h, the modulation index was m = 1.4%, and the flux density of the variable component was S var = 126 mJy.  相似文献   

18.
Results of polarization observations of gas-dust condensations obtained on the Nançay radio telescope in the 1665 and 1667 MHz OH lines in all four Stokes parameters are reported. Seven OH maser sources associated with methanol masers were selected for this study. The goal was to estimate the magnetic fields in methanol condensations from the Zeeman splitting of OH maser lines associated with the methanol masers. The Gaussian parameters of features in the OH spectra are presented, and their polarization parameters are estimated: the degree of circular polarization m C , flux density in linear polarization p, and degree of linear polarization m L . The magnetic field intensity B has been estimated from the Zeeman splitting of the OH lines and approximation of the Stokes parameter V from the derivative of Stokes parameter I. B varies from ≤0.5 to 1.4 mG for different sources. The association of OH masers with methanol emission has been analyzed; the magnetic fields of OH masers in interstellar condensations associated with Class I methanol masers can be determined more reliably than the fields in interstellar condensations with OH masers associated with Class II methanol emission, and have higher values. The sizes of the studied regions suggest they may be bound structures such as Bok globules, small IRDC clouds, or protoplanetary disks.  相似文献   

19.
An improved method has been used for rapid determination of the ionic strength (I) and the salinity of Apulian groundwaters. The parameters required are the electrolytic conductivity (EC) and the total solute concentration (CT) of the solutions. A simple empirical relation between I, EC and CT is presented. The relation holds over a wide concentration and composition range. The combined use of CT and of the ratio ICT is shown to be effective in defining the salinity of groundwaters.  相似文献   

20.
Observations of eclipses of the radio pulsar B1259-63 by the disk of its Be-star companion SS 2883 provide an excellent opportunity to study the winds of stars of this type. The eclipses lead to variations in the radio flux (due to variations in the free-free absorption), dispersion measure, rotation measure, and linear polarization of the pulsar. We have carried out numerical modeling of the parameters of the Be-star wind and compared the results with observations. The analysis assumes that the Be-star wind has two components: a disk wind in the equatorial plane of the Be star with a power-law fall-off in the electron density n e with distance from the center of the star \(\rho (n_e \sim \rho ^{ - \beta _o } )\), and a spherical wind above the poles. The parameters for a disk model of the wind are estimated. The disk is thin (opening angle 7.5°) and dense (electron density at the stellar surface n0e ～ 1012 cm?3, β0 = 2.55). The spherical wind is weak (n0e ? 109 cm?3, β0 = 2). This is the first comparison of calculated and observed fluxes of the pulsating radio emission.  相似文献   

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