585 research outputs found
Influences of neutron star parameters on evolutions of different types of pulsar; evolutions of anomalous X-ray pulsars, soft gamma repeaters and dim isolated thermal neutron stars on the P-\.{P} diagram
Influences of the mass, moment of inertia, rotation, absence of stability in
the atmosphere and some other parameters of neutron stars on the evolution of
pulsars are examined. It is shown that the locations and evolutions of soft
gamma repeaters, anomalous X-ray pulsars and other types of pulsar on the
period versus period derivative diagram can be explained adopting values of
B G for these objects. This approach gives the possibility to explain
many properties of different types of pulsar.Comment: 18 pages, 1 figur
Evaluation of intermolecular interaction energy using one-range addition theorems for – ETO and Coulomb-Yukawa like correlated interaction potentials with integer and noninteger indices
Effects of the background radiation on radio pulsar and supernova remnant searches and the birth rates of these objects
In different directions of the Galaxy the Galactic background radio radiation
and radiation of complex star formation regions which include large number of
OB associations have different influences on radio pulsar (PSR) and supernova
remnant (SNR) searches. In this work we analyse the effects of these background
radiations on the observations of PSRs at 1400 MHz and SNRs at 1000 MHz. In the
interval l=0 the PSRs with flux F0.2 mJy and the SNRs
with surface brightness WmHzsr are
observable for all values of l and b. All the SNRs with
WmHzsr can be observed in the
interval 60l. We have examined samples of PSRs and SNRs to
estimate the birth rates of these objects in the region up to 3.2 kpc from the
Sun and also in the Galaxy. The birth rate of PSRs is about one in 200 years
and the birth rate of SNRs is about one in 65 years in our galaxy.Comment: revised versio
Sturm-Liouville operators on time scales
We establish the connection between Sturm-Liouville equations on time scales
and Sturm--Liouville equations with measure-valued coefficients. Based on this
connection we generalize several results for Sturm-Liouville equations on time
scales which have been obtained by various authors in the past.Comment: 12 page
Hard X-Ray flux upper limits of central compact objects in supernova remnants
We searched for hard X-ray (20–300 keV) emission from nine central compact
objects (CCOs) 1E 1207.4−5209, 1WGA J1713−3949, J082157.5−430017,
J085201.4−461753, J1601−5133, J1613483−5055, J181852.0−150213,
J185238.6+004020, and J232327.9+584843 with the INTEGRAL observatory.
We applied spectral imaging analysis and did not detect any of the sources
with luminosity upper limits in the range of 1033-1034 ergs/s in the 20-75 keV
band. For nearby CCOs (< 4 kpc) the upper limit luminosities are an order
of magnitude lower than the measured persistent hard X-ray luminosities of
AXPs. This may indicate that the central compact objects are low magnetic
field systems with fallback disks around them
Nanotransformation and current fluctuations in exciton condensate junctions
We analyze the nonlinear transport properties of a bilayer exciton condensate
that is contacted by four metallic leads by calculating the full counting
statistics of electron transport for arbitrary system parameters. Despite its
formal similarity to a superconductor the transport properties of the exciton
condensate turn out to be completely different. We recover the generic features
of exciton condensates such as counterpropagating currents driven by excitonic
Andreev reflections and make predictions for nonlinear transconductance between
the layers as well as for the current (cross)correlations and generalized
Johnson-Nyquist relationships. Finally, we explore the possibility of
connecting another mesoscopic system (in our case a quantum point contact) to
the bottom layer of the exciton condensate and show how the excitonic Andreev
reflections can be used for transforming voltage at the nanoscale.Comment: 5 pages, 4 figures, accepted by PR
An integrable discretization of KdV at large times
An "exact discretization" of the Schroedinger operator is considered and its
direct and inverse scattering problems are solved. It is shown that a
differential-difference nonlinear evolution equation depending on two arbitrary
constants can be solved by using this spectral transform and that for a special
choice of the constants it can be considered an integrable discretization of
the KdV equation at large times. An integrable difference-difference equation
is also obtained.Comment: 12 page
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