2,184 research outputs found
Giant acceleration in slow-fast space-periodic Hamiltonian systems
Motion of an ensemble of particles in a space-periodic potential well with a
weak wave-like perturbation imposed is considered. We found that slow
oscillations of wavenumber of the perturbation lead to occurrence of directed
particle current. This current is amplifying with time due to giant
acceleration of some particles. It is shown that giant acceleration is linked
with the existence of resonant channels in phase space
6-meter telescope observations of three dwarf spheroidal galaxies with very low surface brightness
Dwarf spheroidal galaxies (dSphs) are mostly investigated in the Local Group.
DSphs are difficult targets for observations because of their small size and
very low surface brightness. Here we measure spectroscopic and photometric
parameters of three candidates for isolated dSphs, KKH65=BTS23, KK180, and
KK227, outside the Local Group. The galaxies are found to be of low metallicity
and low velocity dispersion. They are among the lowest surface brightness
objects in the Local Universe. According to the measured radial velocities,
metallicities, and structural and photometric parameters, KKH65 and KK227 are
representatives of the ultra-diffuse quenched galaxies. KKH65 and KK227 belong
to the outer parts of the groups NGC3414 and NGC5371, respectively. KK180 is
located in the Virgo cluster infall region.Comment: 4 pages, 3 figures, 3 tables, 3 Appendices with 5 figures and 3
table
Selective Transport and Mobility Edges in Quasi-1D Systems with a Stratified Correlated Disorder
We present analytical results on transport properties of many-mode waveguides
with randomly stratified disorder having long-range correlations. To describe
such systems, the theory of 1D transport recently developed for a correlated
disorder is generalized. The propagation of waves through such waveguides may
reveal a quite unexpected phenomena of a complete transparency for a subset of
propagating modes. We found that with a proper choice of long-range
correlations one can arrange a perfect transparency of waveguides inside a
given frequency window of incoming waves. Thus, mobility edges are shown to be
possible in quasi-1D geometry with correlated disorder. The results may be
important for experimental realizations of a selective transport in application
to both waveguides and electron/optic nanodevices.Comment: RevTex, 4 pages, no figure
Signum Function Method for Generation of Correlated Dichotomic Chains
We analyze the signum-generation method for creating random dichotomic
sequences with prescribed correlation properties. The method is based on a
binary mapping of the convolution of continuous random numbers with some
function originated from the Fourier transform of a binary correlator. The goal
of our study is to reveal conditions under which one can construct binary
sequences with a given pair correlator. Our results can be used in the
construction of superlattices and waveguides with selective transport
properties.Comment: 14 pages, 7 figure
The maximum depth of shower with E sub 0 larger than 10(17) eV on average characteristics of EAS different components
The extensive air shower (EAS) development model independent method of the determination of a maximum depth of shower (X sub m) is considered. X sub m values obtained on various EAS parameters are in a good agreement
Estimation of composition of cosmic rays with E sub zero approximately equals 10(17) - 10(18) eV
Fluctuations of the shower maximum depth obtained from analysis of electron and muon fluctuations and the extensive air showers (EAS) Cerenkov light on the Yakutsk array data and data of other arrays are considered. On the basis of these the estimation of composition of primaries with E sub 0 = 5.10 to the 17th power eV is received. Estimation of gamma-quanta flux with E sub 0 10 to the 17th power eV is given on the poor-muon showers
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