for Two-Component Power Law Irregularity Spectra Charles S. Carrano, Charles L. Rino Institute for Scientific Research Boston College ABSTRACT We extend the phase screen power law theory for ionospheric scintillation to account for the case where the refractive index irregularities follow a two-component power law spectrum. The twocomponent model includes, as special cases, an unmodified power ...

We describe local light-ray rotation in terms of complex refractive indices. We show that Fermat’s principle holds, and we derive an extended Snell’s law. The change in the angle of a light ray with respect to the normal to a refractive-index interface is described by the modulus of the refractive-index ratio, the rotation around the interface normal is described by the argument of the refracti...

We derive a formal description of local light-ray rotation in terms of complex refractive indices. We show that Fermat's principle holds, and we derive an extended Snell's law. The change in the angle of a light ray with respect to the normal of a refractive index interface is described by the modulus of the refractive index ratio; the rotation around the interface normal is described by the ar...

In this work, a contrast index for quantifying the perceived contrast in an image is proposed. The index is based on Weber’s law and takes into account background estimation through the erosion of opening by reconstruction. The performance of our proposal is illustrated with a set of images processed by contrast mapping and compared with two contrast measures given in the literature.

Abstract. We report the results of extracting the hard X-ray continuum spectrum of Cas A SNR from RXTE/PCA Target of Opportunity (TOO) observations and CGRO/OSSE observations. The data can rule out the single thermal bremsstrahlung model for Cas A continuum between 2 and 150 keV. The single power law model gives a mediocre fit (∼5%) to the data with a power-law index, Γ = 2.94±0.02. A model wit...

Aims. The 0.5-150 keV broad-band spectra of a sample of nine bright type 1 Seyfert galaxies are analyzed here. These sources have been discovered/detected by INTEGRAL and subsequently observed with XMM–Newton for the first time with high sensitivity below 10 keV. The sample, although small, is representative of the population of type 1 AGN which are now being observed above 20 keV. Methods. The...

The two nearby starburst galaxies M82 and NGC 253 were observed for ∼ 100 ksec over a 10-month period in 1997. An increase of the M82 flux by a factor ∼ 2 was measured during the period July-November, when compared with the flux measured earlier in 1997. The flux measured in the field centered on M82 includes ∼ 38% of the emission from the Seyfert 1 galaxy M81. The best-fitting model for the ea...

Dow Jones Index time series exhibit irregular or fractal fluctuations on all time scales from days, months to years. The apparently irregular (nonlinear) fluctuations are selfsimilar as exhibited in inverse power law form for power spectra of temporal fluctuations. Inverse power law form for power spectra of fractal fluctuations in space or time is generic to all dynamical systems in nature and...

The shock-acceleration theory predicts a power-law energy spectrum in the test particle approximation, and there are two ways to calculate a power-law index, Peacock’s approximation and Vietri’s formulation. In Peacock’s approximation, it is assumed that particles cross a shock front many times and energy-gains for each step are fully uncorrelated. On the other hand, correlation of the distribu...

Nonrotating black holes in three and four dimensions are shown to possess a canonical entropy obeying the Bekenstein-Hawking area law together with a leading correction (for large horizon areas) given by the logarithm of the area with a universal finite negative coefficient, provided one assumes that the quantum black hole mass spectrum has a power-law relation with the quantum area spectrum fo...