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Faraday rotation measure synthesis in AIPS. The new task FARS

Faraday rotation measure synthesis in AIPS. The new task FARS. L. Kogan, F. Owen National Radio AstronomyObservatory Socorro, NM USA. The observed signal for an example of Faraday rotating media. Faraday rotation measure synthesis. Shifting along the lambda square axis.

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Faraday rotation measure synthesis in AIPS. The new task FARS

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  1. Faraday rotation measure synthesis in AIPS. The new task FARS L. Kogan, F. Owen National Radio AstronomyObservatory Socorro, NM USA 22 July 2011 Moscow

  2. The observed signal for an example of Faraday rotating media 22 July 2011 Moscow

  3. Faraday rotation measure synthesis 22 July 2011 Moscow

  4. Shifting along the lambda square axis 22 July 2011 Moscow

  5. RMTF functions for 8 frequencies in (1-2) GHzThe first row: (Re, Im) for the original set of The second row: (Re, Im) for the shifted set of 22 July 2011 Moscow

  6. Example of shift of the UV coverage center. 22 July 2011 Moscow

  7. Subtracting real and imaginary parts of the Fourier transform at the position of maximum of its amplitude 22 July 2011 Moscow

  8. The task carries out:1. Picks up the U polarization data from the first input image as real and Q polarization data from the second input image, as imaginary of the complex input data2. Fourier transform of the complex input data along the lambda square axis3. Clean out the given number of complex components using the pre -calculated RMTF (as DB)4. The output images (cubes) can be either the full Fourier transform along axis for each image pixel (CLEANed or not CLEANed), or the 3 parameters of the only complex component. Only one output (CUBE) is used at the last case.5. The cleaned components can be convolved with real part of the RMTF(DB), or with the Gaussian of the given FWHM.6. The residual (Re, Im, or Amp) can be sent to the output also.7. The RMTF (DB) function (Re, Im, or Amp) can be sent to the output also under control of input parameters The AIPS task FARS 22 July 2011 Moscow

  9. The 3 parameters recorded into output image at the case of only one component.The most typical case. 22 July 2011 Moscow

  10. One-D Clean of rotation measure spectrum and following convolution with Gaussian of FWHM=20 1/m^2; Only 8 frequencies were used The first row: 2 real components: 1. ampl. =0.2 , RM=-80; 2. ampl.= 1.0 , RM =100The second row: 2 complex components: 1. 0.2*expj ( /4)=(0.14+j0.14), RM=-80; 2. 1.0*expj ( /3)=(0.5+j0.86), RM =100 The left column is RE; the right column is IM 22 July 2011 Moscow

  11. One-DClean of rotation measure spectrum and following convolution with Gaussian of FWHM=20 1/m^2; 101 frequencies are used2 complex components: 1. 0.2*expj(pi/4)=(0.14+j0.14), RM=-80; 2. 1.0*expj(pi/3)=(0.5+j0.86), RM =100 The left column is RE; the right column is IM 22 July 2011 Moscow

  12. CONCLUSIONS 1.The AIPS’ task FARS is ready to serve the users interesting in Faraday rotation synthesis 2. The especially good results are expected with EVLA data, where the better frequency axis filling is expected 22 July 2011 Moscow

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