Add requirement for minimum number of events in a time bin for background consideration (#2713)

Josh Cardenzana · Jürgen Knödlseder
1 parent bac73c21
Showing 2 changed files with 15 additions and 3 deletions
src/ctfindvar/ctfindvar.cpp
src/ctfindvar/ctfindvar.hpp
@@ -421,11 +421,19 @@ void ctfindvar::get_variability_sig(const int&amp; pix_number,
         for (int i=0; i< nbins; i++) //looping over all the GTIs of the pixel
         {
            alpha=0;
-           if (accepted_bin_bckg_vector[i]==0) continue;     //the GTI is discared from bckg calculation and not checked again.
+           //the GTI is discared from bckg calculation and not checked again.
+           if (accepted_bin_bckg_vector[i]==0) {
+               continue;
+           } 
+           // Check if bin fails minoff check
+           else if (m_counts(pix_number, i) < m_minoff) {
+               accepted_bin_bckg_vector[i]=0;
+               continue;
+           }
            int background_count=0;
            for (int j=0;j<nbins;j++)  // for one GTI selected (i), looping over all the others (j).
            {
-                if (j!=i &&accepted_bin_bckg_vector[j]==1)
+                if (j!=i && accepted_bin_bckg_vector[j]==1)
                 {
                     background_count+= m_counts(pix_number, j);
                     alpha++;
@@ -436,7 +444,7 @@ void ctfindvar::get_variability_sig(const int&amp; pix_number,
            non = m_counts(pix_number, i); 
            noff = background_bin_array[i];
            alpha = (1./alpha);
-          
+
            ///////////////////////////////////////////////////////////////////////////////// 
            // Compute sensitivity in Gaussian sigma
            double alpha1 = alpha + 1.0;
@@ -643,6 +651,9 @@ void ctfindvar::get_parameters(void)
     m_emin = GEnergy((*this)["emin"].real(), "TeV");
     m_emax = GEnergy((*this)["emax"].real(), "TeV");
+    // Get minimum counts for a bin to be considered in Noff calculation
+    m_minoff = (*this)["minoff"].real();
+
     // Write parameters into logger
     log_parameters(TERSE);
@@ -89,6 +89,7 @@ protected:
     GSkyMap  m_counts;                 //!< Counts for each time interval
     GGti     m_gti;                    //!< List of time intervals
     GModels  m_inmodel;                //!< List of models for source positions
+    double   m_minoff;                 //!< Minimum counts for use in significance calculation
     GSkyMap  m_peaksigmap;             //!< Skymap holding the maximum significance
     GNdarray m_pixsigsrc;              //!< Store distributions of the source significances
     GNdarray m_pixsigmax;              //!< Store distribution for pixel with max significance