525 research outputs found
Inverse Compton scattering in mildly relativistic plasma
We investigated the effect of inverse Compton scattering in mildly
relativistic static and moving plasmas with low optical depth using Monte Carlo
simulations, and calculated the Sunyaev-Zel'dovich effect in the cosmic
background radiation. Our semi-analytic method is based on a separation of
photon diffusion in frequency and real space. We use Monte Carlo simulation to
derive the intensity and frequency of the scattered photons for a monochromatic
incoming radiation. The outgoing spectrum is determined by integrating over the
spectrum of the incoming radiation using the intensity to determine the correct
weight. This method makes it possible to study the emerging radiation as a
function of frequency and direction. As a first application we have studied the
effects of finite optical depth and gas infall on the Sunyaev-Zel'dovich effect
(not possible with the extended Kompaneets equation) and discuss the parameter
range in which the Boltzmann equation and its expansions can be used. For high
temperature clusters ( keV) relativistic corrections based
on a fifth order expansion of the extended Kompaneets equation seriously
underestimate the Sunyaev-Zel'dovich effect at high frequencies. The
contribution from plasma infall is less important for reasonable velocities. We
give a convenient analytical expression for the dependence of the cross-over
frequency on temperature, optical depth, and gas infall speed. Optical depth
effects are often more important than relativistic corrections, and should be
taken into account for high-precision work, but are smaller than the typical
kinematic effect from cluster radial velocities.Comment: LateX, 30 pages and 11 figures. Accepted for publication in the
Astrophysical Journa
Quantum interference in the classically forbidden region: a parametric oscillator
We study tunneling between period two states of a parametrically modulated
oscillator. The tunneling matrix element is shown to oscillate with the varying
frequency of the modulating field. The effect is due to spatial oscillations of
the wave function and the related interference in the classically forbidden
region. The oscillations emerge already in the ground state of the oscillator
Hamiltonian in the rotating frame, which is quartic in the momentum.Comment: Submitted to PR
Multiphoton antiresonance in large-spin systems
We study nonlinear response of a spin with easy-axis anisotropy. The
response displays sharp dips or peaks when the modulation frequency is
adiabatically swept through multiphoton resonance. The effect is a consequence
of a special symmetry of the spin dynamics in a magnetic field for the
anisotropy energy . The occurrence of the dips or peaks is
determined by the spin state. Their shape strongly depends on the modulation
amplitude. Higher-order anisotropy breaks the symmetry, leading to sharp steps
in the response as function of frequency. The results bear on the dynamics of
molecular magnets in a static magnetic field.Comment: Submitted to PR
Optical Identification of Four Hard X-ray Sources from the Swift All-Sky Survey
We present the results of our optical identifications of four hard X-ray
sources from the Swift all-sky survey. We obtained optical spectra for each of
the program objects with the 6-m BTA telescope (Special Astrophysical
Observatory, Russian Academy of Sciences, Nizhnii Arkhyz), which allowed their
nature to be established. Two sources (SWIFT J2237.2+6324} and SWIFT
J2341.0+7645) are shown to belong to the class of cataclysmic variables
(suspected polars or intermediate polars). The measured emission line width
turns out to be fairly large (FWHM ~ 15-25 A), suggesting the presence of
extended, rapidly rotating (v~400-600 km/s) accretion disks in the systems.
Apart from line broadening, we have detected a change in the positions of the
line centroids for SWIFT J2341.0+7645, which is most likely attributable to the
orbital motion of the white dwarf in the binary system. The other two program
objects (SWIFT J0003.3+2737 and SWIFT J0113.8+2515) are extragalactic in
origin: the first is a Seyfert 2 galaxy and the second is a blazar at redshift
z=1.594. Apart from the optical spectra, we provide the X-ray spectra for all
sources in the 0.6-10 keV energy band obtained from XRT/Swift data.Comment: 9 pages, 6 figures, will be published in Astronomy Letters, 38, No.5,
pp.281-289 (2012
Backward asymmetry of the Compton scattering by an isotropic distribution of relativistic electrons: astrophysical implications
The angular distribution of low-frequency radiation after single scattering
by an isotropic distribution of relativistic electrons considerably differs
from the Rayleigh angular function. In particular, the scattering by an
ensemble of ultra-relativistic electrons obeys the law p=1-cos(alpha), where
alpha is the scattering angle; hence photons are preferentially scattered
backwards. We discuss some consequences of this fact for astrophysical
problems. We show that a hot electron-scattering atmosphere is more reflective
than a cold one: the fraction of incident photons which become reflected having
suffered a single scattering event can be larger by up to 50 per cent in the
former case. This should affect the photon exchange between cold accretion
disks and hot coronae or ADAF flows in the vicinity of relativistic compact
objects; as well as the rate of cooling (through multiple inverse-Compton
scattering of seed photons supplied from outside) of optically thick clouds of
relativistic electrons in compact radiosources. The forward-backward scattering
asymmetry also causes spatial diffusion of photons to proceed slower in hot
plasma than in cold one, which is important for the shapes of Comptonization
spectra and the time delays between soft and hard radiations coming from
variable X-ray sources.Comment: 20 pages, 3 figures, to appear in Astronomy Letters, added reference
BASIC ELEMENTS OF THE MECHANISM OF MANAGEMENT OF THE INTELLECTUAL CAPITAL
The modified multicomponent organizational and economic mechanism of management of the intellectual capital has considered. This is the technical system necessary for achievement of the goals, the organization sets, using symbiotic connection of the valid economic model and the intellectual capital. The mechanism is based on the building an optimal objective function to achieve the goals of the company. The implementation of that mechanism in practice will substantially allow innovation-active organizations to improve the quality of developed and adopted management decisions
X-ray line formation in the spectrum of SS 433
The mechanisms for the formation of X-ray lines in the spectrum of SS 433 are
investigated by taking into account the radiative transfer inside the jets. The
results of Monte Carlo numerical simulations are presented. The effect of a
decrease in line intensity due to scattering inside the jet turns out to be
pronounced, but it does not exceed 60% in magnitude on the entire grid of
parameters. The line broadening due to scattering, nutational motion, and the
contribution of satellites can lead to overestimates of the jet opening angle
from the line widths in Chandra X-ray observations. The fine structure
of the lines turns out to be very sensitive to the scattering effects. This
makes its investigation by planned X-ray observatories equipped with
high-resolution spectrometers (primarily Astro-H) a powerful tool for
diagnosing the parameters of the jets in SS 433.Comment: 23 pages, 14 figures, to be published in Astronomy Letters, v. 38, n.
7, p. 443 (2012
THE ANALYSIS OF STRUCTURE OF INNOVATIVE CAPACITY OF THE ENTERPRISE ON THE EXAMPLE OF THE AVIATION INDUSTRY
It is shown that as one of the main and signicant components of eective functioning of the hi-tech enterprise the high percent of an intellectual component in its structure acts. Indicators by means of which components of innovative potential can be estimated are considered. On the basis of the carried-out assessment of the key components which are a part of innovative potential the modied formula of calculation of the expected size of the prot got from sale of hi-tech production which the enterprise makes independently is oered
THEORETICAL BASES OF MANAGEMENT OF INNOVATIVE DEVELOPMENT OF THE ENTERPRISE OF MECHANICAL ENGINEERING
In the article it is shown that the most limited type of resources during creation of innovative production in domestic engineering industry are financial resources. Economic efficiency of innovative activity directly depends on nature of their formation and distribution. The algorithm of formation and distribution of the budgetary and extrabudgetary financial resources of the enterprise of mechanical engineering in the course of implementation of the innovative program is considered
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