Friday, May 20, 2005

GravStat 2005: Woan

Search for quasi-sinusoidal signal from triaxial NS. Large number of parameters, sime of large dimension. However signal is believed to be coherent on long timescales and may be phase-locked to the radio pulse.

If searching for a radio pulsar only need narrow bandwidth so can be in a clear region of the frequency spectrum. If frequency is not known then problem is that instrument has many lines that can be picked up by matched filters. However instrumental lines will not exhibit correct doppler/antenna pattern modulations.

Time-domain searches targeted MCMC over narrow parameter space. Frequency domain searches for isolated lines. Incoherent searches - Hough transform, stack-slide, powerflux.
Incoherent techniques are worth doing because coherent searches are over such a large parameter space that a source must be strong to be statistically significant.

LISA confusion - Umstatter et al 2005 blind detection and parameter estimation of 100 unkown sinusoids in noise of unknown variance. Frequentist approaches are fast but clumsy when making a final statement on sensitivity - can we recast in B terms. Is it sensible to use worsre case scenarios for upper limits ?

Given a posterior how do we make a statement about whether a detection has been made ? What is the best credible interval to use ?

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