XMM-Newton Science Analysis System


eslewchain (eslewchain-1.7.1) [xmmsas_20160201_1833-15.0.0]

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Algorithm

   Find an event file in SAS_ODF

   Find the celestial position of the start of the slew

   If (X range of event file > Y range) { 
      NRANGES = (XMAX - XMIN) / 72000 + 1
   else
      NRANGES = (YMAX - YMIN) / 72000 + 1
   }

   for i=1 to NRANGES

     Calculate the minimum and maximum for the main axis:
      ax1min = (XMIN or YMIN) + 72000 * (i-1)
      ax1max = ax1min + 72000

     find ranges in second axis which have value of ax1 between min and max
     NB: There can be >1 range if the slew doubles back

     for j=1 to Nranges_ax2

        Filter the event file with this X and Y range:
         evselect table=eventfile 
                  expression=(X in [$x1:$x2])&&(Y in [$y1:$y2])
                  withfilteredset=yes filteredset=<filtfilename>

        Attitude correct the filtered event file to the centre pixel: 
         attcalc eventset=<filtfilename> refpointlabel=user 
         nominalra=<ra> nominaldec=<dec>

        Find the X, Y range of the attitude-corrected event file

        Get the RA, DEC of the centre of the filtered file

        Create an image name stem from the central RA and DEC
         Iname = I<rev><obsid><ra><dec>

        Create an unfiltered image from this event file as a diagnostic:
         evselect table=<filtfilename> imageset=<Iname"_wartsnall.ds">

        Create images in each energy band
         evselect table=<filtfilename> imageset=<Iname"_b1.ds">
                  expression=(FLAG==0)&&(PI in [200:500])&&(PATTERN==0)

         evselect table=<filtfilename> imageset=<Iname"_b2.ds">
                  expression=(FLAG==0)&&(PI in [501:1000])&&(PATTERN<=4)

         etc.

        Make exposure maps
         eexpmap imageset=Idel.fits eventset=<filtfilename> 
                 expimageset=$expb4 $expb5 $expb0",
                 "pimin=2000 200 200","pimax=12000 2000 12000" 
       
        Add together 0.2-0.5, 0.5-1.0, 1.0-2.0 and 2-12 keV images to
        make the b0 and b5 images using "farith"

     } End of Second Axis loop
   } End of First axis loop