Документ взят из кэша поисковой машины. Адрес оригинального документа : http://xmm.vilspa.esa.es/sas/7.0.0/doc/rgsregions/node8.html
Дата изменения: Thu Jun 29 00:33:01 2006
Дата индексирования: Sat Dec 22 11:50:31 2007
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Поисковые слова: comet tail

XMM-Newton Science Analysis System


rgsregions (rgsregions-1.19.2) [xmmsas_20060628_1801-7.0.0]

Meta Index / Home Page

Algorithm

$\bullet$ SOURCE SELECTIONS

  if --procsrcsexpr is non-empty:
    use --procsrcsexpr to select sources for image and order regions
    if --setflags is true:
      update SRC_SELECT column with this result
  else:
    initialize selected sources from SRC_SELECT column

$\bullet$ EXCLUDED SOURCE SELECTIONS

  if --exclsrcsexpr is non-empty:
    use --exclsrcsexpr to select sources for exclusion from background region
    if --setflags is true:
      update BACK_SELECT column with this result
  else:
    initialize excluded sources from BACK_SELECT column

$\bullet$ SPATIAL BACKGROUND REGION

  unless a correctly specified or protected background region exists:
    initialize empty region
    for each node:
      add polygon bounding the exposed surface
      for each excluded source:
        intersect polygon excluding --xpsfexcl percent of cross-dispersion PSF
    scan region for total number of enclosed pixels
    add region to source list

$\bullet$ IMAGE AND ORDER REGIONS

  for each selected source:

    unless a correctly specified or protected image region exists:
      initialize empty region
      for each node:
        if Spectroscopy:
          add polygon enclosing the xdsp PSF from --xpsfbelow to --xpsfabove
        else: (High Time Resolution)
          add polygon enclosing all exposure
      scan region for total number of enclosed pixels
      add region to source list

    for each order (1 to --maxorder):

       unless a correctly specified or protected order region exists:
         initialize empty region
         for each node:
           add polygon enclosing --pdistincl percent of PI distribution
         add excluded rectangle to each node with a calibration source
         scan region for total number of enclosed pixels
         add region to source list

       unless Spectroscopy or a correctly specified or protected background order region exists:
         initialize empty region
         for each node:
           if first order and CCD < 4: switch to second order
           construct polygon enclosing --pdistincl percent of PI distribution
           transform it by reflecting around top vertex at each vertex pair
           add transformed polygon to region
         add excluded rectangle to each node with a calibration source
         scan region for total number of enclosed pixels
         add region to source list