XMM-Newton Science Analysis System


slconv (slconv-2.5) [xmmsas_20141104_1833-14.0.0]

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Algorithm

Pass input source table through selection expression;

if (usecorr) {
  ra  = readColumn(RA_CORR);
  dec = readColumn(DEC_CORR);
} else {
  ra  = readColumn(RA);
  dec = readColumn(DEC);
}

Convert ra, dec to pixel coordinates xima and yima;

# Calculate radii:
foreach i (1 .. numOfRows(sourceTable)) {
  protoRadius(i) = evaluateRadiusExpression();
}

protoMedian = medianValue(protoRadius);
scaledMedian = (protoMedian - minval(protoRadius))
 / (maxval(protoRadius) - minval(protoRadius));

sag = (scaledMedian - radiusbias)
 / (radiusbias * (2 * scaledMedian - 1) - scaledMedian);

foreach i (1 .. numOfRows(sourceTable)) {
  scaledRadius(i) = (protoRadius(i) - minval(protoRadius))
   / (maxval(protoRadius) - minval(protoRadius));

  radius(i) = scaledRadius(i) * (1 + sag)
   / (1 + sag * (2 * scaledRadius(i) - 1));
}

# Sort the sources:
foreach i (1 .. numOfRows(sourceTable)) {
  index(i) = i
}
Sort index in the style requested by --ncutsortstyle;

if (--ncutsortstyle eq 'none') {
  numLastSource = numOfRows(sourceTable);
} else {
  numLastSource = min(numOfRows(sourceTable), --ncut);
}

# Allocate source labels;

# Output:
foreach i (1 .. numLastSource) {
  writeOutputCircle(xima(index(i)), yima(index(i)), radius(index(i)));
}