scholarly journals Angular power spectra of Galactic HI

2006 ◽  
Vol 2 (S237) ◽  
pp. 413-413
Author(s):  
D. A. Green
Keyword(s):  
Power Law ◽  
Galactic Plane ◽  
Power Spectra ◽  
Simple Power ◽  
Angular Scale

AbstractAs an alternative to identifying and then studying particular features seen in Galactic HI 21-cm images, studies of the angular power spectra of the emission provide a concise, statistical description of HI emission. The angular power spectra of several fields near l = 140°, from the Canadian Galactic Plane Survey, as observed with the DRAO Synthesis Telescope, have been analysed in this way. The derived power spectra, which typically cover angular scales from about 0 · 15 to 0 · 9 degree, are generally well-fitted by a simple power-law dependence on angular scale.

scholarly journals X-ray Properties of 3C 111: Separation of Primary Nuclear Emission and Jet Continuum

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 219
Author(s):  
Elena Fedorova ◽  
B.I. Hnatyk ◽  
V.I. Zhdanov ◽  
A. Del Popolo
Keyword(s):  
Accretion Disk ◽  
Power Law ◽  
Line Emission ◽  
High Energy ◽  
Power Law Model ◽  
X Ray ◽  
Additional Information ◽  
Observational Dataset ◽  
Simple Power ◽  
Photon Index

3C111 is BLRG with signatures of both FSRQ and Sy1 in X-ray spectrum. The significant X-ray observational dataset was collected for it by INTEGRAL, XMM-Newton, SWIFT, Suzaku and others. The overall X-ray spectrum of 3C 111 shows signs of a peculiarity with the large value of the high-energy cut-off typical rather for RQ AGN, probably due to the jet contamination. Separating the jet counterpart in the X-ray spectrum of 3C 111 from the primary nuclear counterpart can answer the question is this nucleus truly peculiar or this is a fake “peculiarity” due to a significant jet contribution. In view of this question, our aim is to estimate separately the accretion disk/corona and non-thermal jet emission in the 3C 111 X-ray spectra within different observational periods. To separate the disk/corona and jet contributions in total continuum, we use the idea that radio and X-ray spectra of jet emission can be described by a simple power-law model with the same photon index. This additional information allows us to derive rather accurate values of these contributions. In order to test these results, we also consider relations between the nuclear continuum and the line emission.

scholarly journals HELICAL MAGNETIC FIELDS FROM INFLATION

2009 ◽  
Vol 18 (09) ◽  
pp. 1395-1411 ◽  
Author(s):  
LEONARDO CAMPANELLI
Keyword(s):  
Magnetic Fields ◽  
Power Law ◽  
Background Field ◽  
Wave Number ◽  
Conformal Time ◽  
De Sitter ◽  
Simple Power ◽  
Dimensionless Constant ◽  
Real Positive Number

We analyze the generation of seed magnetic fields during de Sitter inflation considering a noninvariant conformal term in the electromagnetic Lagrangian of the form [Formula: see text], where I(ϕ) is a pseudoscalar function of a nontrivial background field ϕ. In particular, we consider a toy model that could be realized owing to the coupling between the photon and either a (tachyonic) massive pseudoscalar field or a massless pseudoscalar field nonminimally coupled to gravity, where I follows a simple power law behavior I(k,η) = g/(-kη)β during inflation, while it is negligibly small subsequently. Here, g is a positive dimensionless constant, k the wave number, η the conformal time, and β a real positive number. We find that only when β = 1 and 0.1 ≲ g ≲ 2 can astrophysically interesting fields be produced as excitation of the vacuum, and that they are maximally helical.

Prediction of Bubbles, Crashes, and Antibubbles

2017 ◽  
Author(s):  
Didier Sornette
Keyword(s):  
Stock Market ◽  
Case Studies ◽  
Power Law ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Large Market ◽  
Simple Power ◽  
Market Crashes ◽  
Successes And Failures

This chapter examines how to predict stock market crashes and other large market events as well as the limitations of forecasting, in particular in terms of the horizon of visibility and expected precision. Several case studies are presented in detail, with a careful count of successes and failures. After providing an overview of the nature of predictions, the chapter explains how to develop and interpret statistical tests of log-periodicity. It then considers the concept of an “antibubble,” using as an example the Japanese collapse from the beginning of 1990 to the present. It also describes the first guidelines for prediction, a hierarchy of prediction schemes that includes the simple power law, and the statistical significance of the forward predictions.

scholarly journals Review of observational results on γ-ray background: (Invited discourse)

1970 ◽  
Vol 37 ◽  
pp. 269-279 ◽  
Author(s):  
G. W. Clark ◽  
G. P. Garmire ◽  
W. L. Kraushaar
Keyword(s):  
Power Law ◽  
Strong Evidence ◽  
Galactic Plane ◽  
High Energy ◽  
Electromagnetic Spectrum ◽  
Γ Rays ◽  
Γ Ray ◽  
Region 10

Recent observations in the X- and γ-Ray region of the electromagnetic spectrum have given strong evidence for the existence of an extragalactic intensity with a slowly steepening power law spectrum in the region 103 to 108 eV. Further data from the OSO-III high energy γ-Ray detector are in agreement with earlier published reports, and suggest that the γ-Rays from high galactic latitudes have a softer spectrum than those from the galactic plane.

scholarly journals HIERARCHICAL MASSES AND UNIVERSAL MIXING IN QUARK–LEPTON MASS MATRICES

2013 ◽  
Vol 28 (32) ◽  
pp. 1350146 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
HIROYUKI NISHIURA
Keyword(s):  
Power Law ◽  
Simple Power ◽  
Mass Matrices ◽  
Mixing Matrix

The universality hypothesis for quark and lepton mixing matrices (CKM and MNS) is further developed. This hypothesis explains why the CKM is almost diagonal whereas the MNS is almost maximally mixed. If this hypothesis is true, the Dirac CP violating phase of the MNS mixing matrix is bounded around π or 0. Quark–lepton mass matrices which realize this hypothesis are constructed, showing simple power law relations among mass matrices for up-type, down-type quarks and neutrinos.

scholarly journals Interplanetary Scintillation Power Spectra

1976 ◽  
Vol 29 (3) ◽  
pp. 201 ◽  
Author(s):  
RG Milne
Keyword(s):  
Power Spectrum ◽  
Power Law ◽  
Scattering Theory ◽  
Power Spectra ◽  
Inverse Power ◽  
Radio Sources ◽  
Interplanetary Scintillation ◽  
Inverse Power Law ◽  
Power Law Index ◽  
Strong Scattering

Power spectrum measurements of interplanetary scintillation at 408 MHz show that an inverse power law spectrum provides the best description for all scintillating radio sources. The inverse power law index is reasonably constant at ~ 2�4 for solar elongation angles 8 > 10�, and this agrees well with spacecraft observations. For 8 < 10� the index apparently decreases with decreasing 8, and this appears to be consistent with recent strong scattering theory. A Bessel analysis attempted in order to detect Fresnel structure proved unsuccessful because of noise on the power spectra.

scholarly journals A deterministic width function model

2003 ◽  
Vol 10 (6) ◽  
pp. 525-529 ◽  
Author(s):  
C. E. Puente ◽  
B. Sivakumar
Keyword(s):  
United States ◽  
Power Law ◽  
Power Spectra ◽  
The United States ◽  
Geometric Method ◽  
River Networks ◽  
Function Model ◽  
Natural Width ◽  
Width Function ◽  
Multifractal Measures

Abstract. Use of a deterministic fractal-multifractal (FM) geometric method to model width functions of natural river networks, as derived distributions of simple multifractal measures via fractal interpolating functions, is reported. It is first demonstrated that the FM procedure may be used to simulate natural width functions, preserving their most relevant features like their overall shape and texture and their observed power-law scaling on their power spectra. It is then shown, via two natural river networks (Racoon and Brushy creeks in the United States), that the FM approach may also be used to closely approximate existing width functions.

scholarly journals Multiple Time Scales in Cataclysmic Variables: The Examples

1995 ◽  
Vol 151 ◽  
pp. 302-305
Author(s):  
Ivan L. Andronov
Keyword(s):  
Power Law ◽  
Accretion Rate ◽  
Power Index ◽  
Cataclysmic Variables ◽  
Power Spectra ◽  
Theoretical Explanation ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Solar Type ◽  
Tt Ari

AbstractDecades of patrol observations of cataclysmic variables (CVs) show variations of the accretion rate also at a time scale of a few years which may be explained by a solar-type activity of the secondary and/or by orientation changes of the magnetic axis of the white dwarf in polars. Secondary photometric periods seen in TT Ari and possibly some other CVs need theoretical explanation. Irregular variability of some objects is characterized by power-law power spectra with a power index depending on the luminosity state of the system.

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