309 research outputs found
The general form of the Euler--Poisson--Darboux equation and application of transmutation method
In the paper we find solution representations in the compact integral form to
the Cauchy problem for a general form of the Euler--Poisson--Darboux equation
with Bessel operators via generalized translation and spherical mean operators
for all values of the parameter , including also not studying before
exceptional odd negative values. We use a Hankel transform method to prove
results in a unified way. Under additional conditions we prove that a
distributional solution is a classical one too. A transmutation property for
connected generalized spherical mean is proved and importance of applying
transmutation methods for differential equations with Bessel operators is
emphasized. The paper also contains a short historical introduction on
differential equations with Bessel operators and a rather detailed reference
list of monographs and papers on mathematical theory and applications of this
class of differential equations.Comment: Electronic Journal of Differential Equations, 201
On fractional powers of the Bessel operator on a semiaxis
In this paper we study fractional powers of the Bessel differential operator
defined on a semiaxis. Some important properties of such fractional powers of
the Bessel differential operator are proved. They include connections with
Legendre functions for kernel representations, fractional integral operators of
Liouville and Saigo, Mellin transform and index laws. Possible applications are
indicated to differential equations with fractional powers of the Bessel
differential operator.Comment: English version (pp. 1--8) and Russian version (pp. 9--18
Quadratic exponential in modified discrete Fourier transform and shifted Gaussian series
In this paper we consider quadratic exponential in two main constructions: as finite Gauss sums and in connection with modified discrete Fourier transforms and also as basis of series in shifted Gaussians. We study spectral properties of modified Fourier discrete transforms, its eigenspaces and eigenvector
Measurement of tensor polarization of deuterons from He-3 -\u3e d plus p breakup at internal momenta up to 0.4 GeV/c
The tensor polarization (rho 20) of deuterons emitted in the p(He-3, d)X reaction at 0 degrees in the lab. system was measured at the Saturne National Laboratory in Sac lay, using the SPES-4 spectrometer with the HYPOM polarimeter in the area of its focal plane. The momentum of the detected deuterons was kept fixed at 3.77 GeV/c, while the momentum of the He-3 beam was varied from 4.60 to 5.66 GeV/c, thus providing a range of internal momenta k of the deuteron inside the He-3 from 0 up to 0.4 GeV/c. The obtained data are compared with the theoretical predictions
Periodic Pattern in the Residual-Velocity Field of OB Associations
An analysis of the residual-velocity field of OB associations within 3 kpc of
the Sun has revealed periodic variations in the radial residual velocities
along the Galactic radius vector with a typical scale length of
lambda=2.0(+/-0.2) kpc and a mean amplitude of fR=7(+/-1) km/s. The fact that
the radial residual velocities of almost all OB-associations in rich
stellar-gas complexes are directed toward the Galactic center suggests that the
solar neighborhood under consideration is within the corotation radius. The
azimuthal-velocity field exhibits a distinct periodic pattern in the region
0<l<180 degrees, where the mean azimuthal-velocity amplitude is ft=6(+/-2)
km/s. There is no periodic pattern of the azimuthal-velocity field in the
region 180<l<360 degrees. The locations of the Cygnus arm, as well as the
Perseus arm, inferred from an analysis of the radial- and azimuthal-velocity
fields coincide. The periodic patterns of the residual-velocity fields of
Cepheids and OB associations share many common features.Comment: 21 page
Confirmation of a Faraday Rotation Measure Anomaly in Cygnus
We confirm the reality of a reversal of the sign of the Faraday Rotation
Measure in the Galactic plane in Cygnus (Lazio et al, 1990), possibly
associated with the Cygnus OB1 association. The rotation measure changes by
several hundred rad/m over an angular scale of . We show that
a simple model of an expanding plasma shell with an enhanced density and
magnetic field, consistent with observations of H emission in this part
of sky, and physically associated with a superbubble of the Cygnus OB1
association, can account for the magnitude and angular scale of this feature.Comment: Submitted to the Astrophysical Journa
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