Phase resolved spectral fitting

1. Use a sorting routine to create a 2-d, time x PH_channel binned dataset. e.g. XSORT.

2. Exposure correct the file to convert it into counts/second e.g. for the XRT.

          ICL> XRTCORR
          XRTCORR version 1.4-6
          INP - Input dataset name /@MID_SPEC/ > TIMPH
          OUT - Output dataset name /@TIMPHC/ >
          RTNAME - Rootname for calibration files /'[HIS.2142]X2142'/ >
          Warning: insufficient event rate data to calculate dead time
                   correction for 19 timebins
          Correction for these bins has been set to 1.0
          Warning: bad eventrate data for 9 timebins
          Correction for these bins has been set to 1.0
          Mean dead time correction : 1.001657
          Mean vignetting correction : 58.66176
          Mean scattering correction : 1.007486
          

3. Fold the data at the known orbital period.

          ICL> FOLDBIN
          FOLDBIN Version 1.2-2
          INP - Enter name of input file /@TIMPHC/ >
          Data is 2 dimensional
          OUT - Enter name of output file > TIMPHCFOLD
          TIME UNITS are seconds
          PERIOD - Enter period for folding > 4128.1
          EPOCH - Enter epoch of phase zero /6775.0817013889/ > 6774.002
          BINS - Enter number of phase bins /8/ > 5
          WEIGHT - Are weighted means required? /NO/ >
          ** VARB is zero - CHISQ may not be correct in output file **
          

4. Having converted the time axis into 5 phase bins, we now want to extract the central 20 % of the orbit.

          ICL> BINSUBSET
          BINSUBSET Version 1.2-0
          INP - Input dataset /@TIMPHC/ > TIMPHCFOLD
          OUT - Output dataset > MIDSPEC
          The axes present are:
           1 Phase
           2 Corrected PHA channel
          AXES - Axis numbers to select on > 1
          The range for axis 1 is 0.1 to 0.9
          AXIS1 - Axis 1 ranges to subset /'0.1:0.9'/ > 0.4:0.6
          

5. We now have a single spectrum to perform spectral fitting on. Create a detector response structure for this datafile. e.g. for the ROSAT-XRT use XRTRESP.

          ICL> XRTRESP
          XRTRESP Version 1.3-4
          INP - Name of source file /@MIDSPEC/ >
          RESPFILE - Name of instrument response matrix file /@X2142_DRPM/ >
          

6. Set up a model for the spectral fit

          ICL> SMODEL
          SMODEL Version 1.0-1
          Input model file :- /scratch/asterix/mod.sdf
          A composite model can be synthesised using + - * ( ) and
          any of the following primitive models:
          AG     galactic interstellar absorption             multiplicative
          AB     intrinsic absorption                         multiplicative
          BR     thermal bremsstrahlung (cosmic)              additive
          PL     power law                                    additive
          BB     black body                                   additive
          WN     Wien                                         additive
          BH     hydrogen bremsstrahlung                      additive
          BP     pseudo-bremsstrahlung                        additive
          PC     cutoff power law                             additive
          CS     Chapline-Stevens Comptonised brems.          additive
          ST     Sunyaev-Titarchuk Comptonisation             additive
          RZ     Raymond-Smith plasma (metals combined)       additive
          LG     Gaussian line                                additive
          LL     Lorentzian line                              additive
         SPEC - Model specification > BR*AG
                              COMPONENT  1
                             **************
        Name: thermal bremsstrahlung (cosmic)          Keyword: BR
         PARAMETER  1 - em10                       (1e60cm**-3/(10kpc)**2)
                        value,min,max =   1.0000       1.00000E-04    10.000
        VALS - New values /'unchanged'/ >
         PARAMETER  2 - temperature                (keV)
                        value,min,max =   5.0000       0.10000        20.000
        VALS - New values /'unchanged'/ >
                              COMPONENT  2
                             **************
        Name: galactic interstellar absorption         Keyword: AG
         PARAMETER  1 - hydrogen column density    (1.0E21 /cm**2)
                        value,min,max =   1.0000       0.00000E+00    20.000
        VALS - New values /'unchanged'/ > 0.28
          

   g) Freeze the hydrogen column density and perform the fit.

          ICL> FREEZE 3
               * hydrogen column density frozen
          ICL> SFIT
          SFIT Version 1.4-1
          ...
          

7. Having finished processing the data - review the history of the final file.

          ICL> hist midspec
          HIST Version 1.8-1
          History of  : /datan5/asterix/midspec.sdf
                        SPEC
          Created     : 9-AUG-91 14:25:16
          Update mode : NORMAL
          Contains    : 5 records
          Record 1:
            Creator: XSORT Version 1.3-5
            Date:    9-AUG-91 14:25:17
          Record 2:
            Creator: XRTCORR version 1.4-6
            Date:    9-AUG-91 15:31:44
            Text:    Input dataset  1:
                        /scratch/asterix/timph.sdf
          Record 3:
            Creator: FOLDBIN Version 1.2-2
            Date:    9-AUG-91 15:36:49
            Text:    Input file :
                        /scratch/asterix/timphc.sdf
                     Folded output file :
                        /scratch/asterix/timphcfold.sdf
                     The data has been folded into a period of 4128.1 seconds
                     The epoch of phase zero was 6774.002
          Record 4:
            Creator: BINSUBSET Version 1.2-0
            Date:    9-AUG-91 15:39:14
            Text:    Input dataset  1:
                       /scratch/asterix/timphcfold.sdf
          Record 5:
            Creator: XRTRESP Version 1.3-4
            Date:    9-AUG-91 15:42:23
            Text:    Set up detector response structure in datafile