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03-02-2011
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Today's Colloquium (Peter Frick): Wavelets and Faraday Rotation Measure Synthesis

Submitter: Colloquium
Description: Speaker: Peter Frick (Institute for Continuous Media Mechanics, Perm, Russia)

The presentation starts by an introduction to wavelet analysis mainly based on examples with an astrophysical background. In the second part of the talk I will discuss in detail the application of wavelet technique to the Faraday Rotation Measure (RM) Synthesis. RM-Synthesis, as a method for analyzing multi-channel observations of polarized radio emission to investigate galactic magnetic fields structures, requires the de finition of complex polarized intensity in the wavelength range -inf < ^2 < inf. The problem is that the measurements at negative ^2 are not possible.

We introduce a simple method for continuation of the observed complex polarized intensity P(^2) into the domain ^2 < 0 using symmetry arguments. The method is suggested in context of magnetic field recognition in galactic disks where the magnetic fi eld is supposed to have a maximum in the equatorial plane. The method is quite simple when applied to a single Faraday-rotating structure on the line of sight. Recognition of several structures on the same line of sight requires a more sophisticated technique.

We introduce a wavelet-based algorithm which allows us to consider a set of isolated structures in the (ϕ, ^2) plane (where ϕ is the Faraday depth). The method essentially improves the possibilities for reconstruction of complicated Faraday structures using the capabilities of modern radio telescopes.
Copyright: Peter Frick
 
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