1,727 research outputs found
Modulation Mechanism of TeV, GeV, and X-ray Emission in LS5039
The emission mechanism of the gamma-ray binary LS5039 in energy bands of TeV,
GeV, and X-ray is investigated. Observed light curves in LS5039 show that TeV
and GeV fluxes anticorrelate and TeV and X-ray fluxes correlate. However, such
correlated variations have not been explained yet reasonably at this stage.
Assuming that relativistic electrons are injected constantly at the location of
the compact object as a point source, and that they lose energy only by the
inverse Compton (IC) process, we calculate gamma-ray spectra and light curves
by the Monte Carlo method, including the full electromagnetic cascade process.
Moreover, we calculated X-ray spectra and light curves by using the resultant
electron distribution. As a result, we are able to reproduce qualitatively
spectra and light curves observed by HESS, Fermi, and Suzaku for the
inclination angle i = 30 dig and the index of injected electron distribution p
= 2.5. We conclude that TeV-GeV anticorrelation is due to anisotropic IC
scattering and anisotropic gamma-gamma absorption, and that TeV-X correlation
is due to the dependence of IC cooling time on orbital phases. In addition, the
constraint on the inclination angle implies that the compact object in LS5039
is a black hole.Comment: 27 pages, 7 figures, published in The Astrophysical Journa
Measurability of kinetic temperature from metal absorption-line spectra formed in chaotic media
We present a new method for recovering the kinetic temperature of the
intervening diffuse gas to an accuracy of 10%. The method is based on the
comparison of unsaturated absorption-line profiles of two species with
different atomic weights. The species are assumed to have the same temperature
and bulk motion within the absorbing region. The computational technique
involves the Fourier transform of the absorption profiles and the consequent
Entropy-Regularized chi^2-Minimization [ERM] to estimate the model parameters.
The procedure is tested using synthetic spectra of CII, SiII and FeII ions. The
comparison with the standard Voigt fitting analysis is performed and it is
shown that the Voigt deconvolution of the complex absorption-line profiles may
result in estimated temperatures which are not physical. We also successfully
analyze Keck telescope spectra of CII1334 and SiII1260 lines observed at the
redshift z = 3.572 toward the quasar Q1937--1009 by Tytler {\it et al.}.Comment: 25 pages, 6 Postscript figures, aaspp4.sty file, submit. Ap
Aerodynamic investigation of an air-cooled axial-flow turbine. Part 2: Rotor blade tip-clearance effects on overall turbine performance and internal gas flow conditions: Experimental results and prediction methods
Total turbine blade performance was investigated while changing the blade tip clearance in three ways. The internal flow at the moving blade outlet point was measured. Experimental results were compared with various theoretical methods. Increased blade clearance leads to decreased turbine efficiency
Deformed Hartree-Fock Calculation of Proton-Rich Nuclei
We perform Hartree-Fock+BCS calculations for even-even nuclei with 2 <= Z <=
82 and N ranging from outside the proton drip line to the experimental frontier
on the neutron-rich side. The ground state solutions are obtained for 737
nuclei, together with shape-coexistence solutions for 480 nuclei. Our method
features the Cartesian-mesh representation of single-particle wavefunctions,
which is advantageous in treating nucleon skins and exotic shapes. The results
are compared with those of the finite-range droplet model of Moller et al. as
well as the experimental values.Comment: 7 pages Latex, 5 postscript figures appended as uufil
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