|
Hellings-Downs Curve
The Hellings-Downs curve (also known as the Hellings and Downs curve) is a theoretical tool used to establish the telltale signature that a galactic-scale pulsar timing array has detected Gravitational wave, gravitational waves, typically of wavelengths \lambda = 1 - 10\,\mathrm. The method entails searching for spatial correlations of the timing residuals from pairs of Pulsar, pulsars and comparing the data with the Hellings-Downs curve. When the data fit exceeds the Standard_deviation#Experiment,_industrial_and_hypothesis_testing, standard ''5 sigma'' threshold, the pulsar timing array can declare detection of gravitational waves. More precisely, the Hellings-Downs curve is the expected correlations of the timing residuals from pairs of pulsars as a function of their angular separation on the sky as seen from Earth. This theoretical correlation function assumes Einstein's general relativity and a gravitational wave background that is Isotropy, isotropic. Pulsar timing array r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Correlation Vs Angular Separation Between Pulsars
In statistics, correlation or dependence is any statistical relationship, whether causality, causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics it usually refers to the degree to which a pair of variables are ''line (geometry), linearly'' related. Familiar examples of dependent phenomena include the correlation between the human height, height of parents and their offspring, and the correlation between the price of a good and the quantity the consumers are willing to purchase, as it is depicted in the demand curve. Correlations are useful because they can indicate a predictive relationship that can be exploited in practice. For example, an electrical utility may produce less power on a mild day based on the correlation between electricity demand and weather. In this example, there is a causality, causal relationship, because extreme weather causes people to use more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
