INFILE Input file of the U,Q dependence on frequency. OUTFILE Output file of the depedence on RM. BLANK=>OUTFILE is not created APARM Parameters for algorithm: 1 number of pixels at half of the Fourier transform output The whole number is 2*APARM(1)+1 2 cell size in 1/m^2 0 => PI/(4*(Lmax^2-Lmin^2)) Lmax,Lmin-max,min lambda at the data 3 0 => regular output 1 => output is RMTF 4 0=> CLEANed Fourier transform 1=> unCLEANed Fourier transform 5 0=>original(shifted back) RE/IM are sent out 1=>the shifted RE/IM are sent out 2=>amplitude and phase of the data are sent out 6 Number of rows to use in INFILE 0=> all rows in INFILE 7 0=> convolve the clean components 1=> no convolve 8 0=> use the Gaussian as the convolve function 1=> use the Re of RMTF as the convolve function 9 full width of Gaussian convolve function, at 0.5 level, in 1/m^2 0 => fit to real RMTF < 0 => fit to amp RMTF 10 what send to output? 0 => sum of CLEAN and residual 1 => CLEAN result 2 => residual GAIN Gain in the CLEAN NITER Maximum number of clean components FLUX Minimum flux of clean component (Jy) OPCODE 'CMPL' - new method Clean 'ZERO' - no shift of lambda^2 else peak amplitude Clean

TARS Type: Task The task is for testing the result of Faraday rotation Synthesis (FARS) Adverbs: INFILE......User-supplied text file giving Q (second column) and U (third column) as a function of frequency (first column). A weight may be given in the fourth column. These cards determine the frequecies that will be used and their weights. Default values for Q and U are 0 while the default weight is 1. Model components (up to 20) may be added to the data contained in the cards described above. If the first symbol is "M", then the following 3 numbers give the parameters of a model component: RM, in 1/m^2; AMP, and Phase in degrees. The models are computed and added to the data given in the main data cards --- if you want no data added to the model, specify Q and U as 0.0 in the data cards. If the first symbol in a row is a semicolon, the row is skipped and acts as a comment. The format of columns in INFILE is free with any number of blank characters between columns. The following is example of an INFILE with 2 components in a model and 3 of the N rows of data ; Input file for TARS With the top rows for model. ; The model rows are started with symbol M ; and includes RM in 1/m^2, AMP and PHASE in Degrees ; RM, 1/m^2 AMP Phase, deg M -600 5 60 M -800 3 0 ; FREQ, Hz Q U weight 1266000000 -3.6542873 -2.3332453 0.9 1276000000 -5.0204344 -1.8241444 1.0 1286000000 -4.3795457 0.393933 0.7 OUTFILE.....The result of calculation of Faraday rotation synthesis is written to this file consist of 4 columns 1. the row number; 2. RM in 1/m^2 3. Amplitude (or Real, depending on APARM(5)) 4. Phase (or Imaginary, depending on APARM(5)) ' ' => results are directed to the message file and message display APARM.......Parameters: the same as in FARS APARM(1) number of pixels at half of the Fourier transform output. The whole number is 2*APARM(1)+1 with zero at the center. The value of APARM(1) should be chosen in accordance of expected range of the Faraday rotation measures and value of CELL (APARM(2)) APARM(2) cell size of the outputs, in 1/m^2. The cell is recomended to be less or around the default value (pi)/4/(lambda^2max - lambda^2min) APARM(3) 0 => regular outputs 1 => outputs are RMTF APARM(4) 0=> CLEANed Fourier transform, using inputs: NITER, FLUX, GAIN. The CLEAN uses the shifed (at lambda^2) data but the cleaned components correspond to the original lambda^2 RE is recorded to the first output IM is recorded to the second output 1=> the uncleaned Fourier transform is recorded RE is recorded to the first output IM is recorded to the second output APARM(5) 0=>original data (RE and IM) are used at the Fourier transform 1=> the shifted (to the center) data (RE, IM) are used at the Fourier transform. This option allows better discrimination of different features at the Fourier transform. 2=> amplitude and phase of the data are sent out. APARM(6) Number of rows to use in INFILE 0=> all rows in INFILE If the first symbol at the infile row .EQ. semicolumn, this row is skipped. THIS SEICOLUMN CONCEPT CAN BE USED FOR SELECTION THE ROWS! APARM(7) 0=> convolve the clean components 1 => no convolve; So just the set of the clean components is sent to the output files No convolution is forced if: uncleaned Fourier is sent out (APARM(4)=1) APARM(8) 0=> use the Gaussian as the convolve function 1=> use the Re of RMTF as the convolve function APARM(9) full width of the Gaussian convolve function, at the 0.5 level, in 1/m^2. 0 -> fit the real part of the RMTF. -1 -> fit the amplitude of the RMTF. If OPCODE='ZERO' the amplitude will be rather wider than the real part, otherwise the two will be similar. APARM(10) What send to the output? 0 => sum of CLEAN and residual 1 => CLEAN result 2 => residual GAIN........Gain in the CLEAN NITER.......Maximum number of clean components 0 => 1 FLUX........Minimum Clean component (Jy) The task can subtract the given number of complex components. On each iteration, the maximum (and its position) of the spectrum amplitude is determined. The complex function RMTF is multiplied by the complex value of the spectrum at the position of the found amplitude maximum and by GAIN. The found function(production) is put by its median on the position of found amplitude maximum, and is subtracted from the having evaluated spectrum. The process of the subtraction is terminated having achieved number of iterations NITER or the flux FLUX. OPCODE......'CMPL' invokes a (much slower) true complex Clean rather than the one that looks for the peak in the amplitude. Does not seem to help. 'ZERO' turns of the shift of lambda^2 in the Fourier transform. The real part of the RMTF gets quite a bit narrower, but the imaginary part becomes significant. Use APARM(9) < 0 to fit a more reasonable restoring Gaussian. other - standard peak in the amplitude Clean.