diff --git a/src/tests/skewedGaussianTest/skewedGaussian.C b/src/tests/skewedGaussianTest/skewedGaussian.C
index 3d8a3d5c..145b3f94 100644
--- a/src/tests/skewedGaussianTest/skewedGaussian.C
+++ b/src/tests/skewedGaussianTest/skewedGaussian.C
@@ -20,6 +20,18 @@ Double_t PofB(Double_t B, Double_t B0, Double_t sm, Double_t sp)
     val = TMath::Exp(-0.5*TMath::Power((B-B0)/sp, 2.0));
   }
 
+  val *= TMath::Sqrt(2.0/TMath::Pi())/(sm+sp);
+
+  return val;
+}
+
+//-------------------------------------------------------------------------
+Double_t PofBext(Double_t B, Double_t B0, Double_t s)
+{
+  Double_t val = 0.0;
+
+  val = 1.0/TMath::Sqrt(2.0*TMath::Pi())/s*TMath::Exp(-0.5*TMath::Power((B-B0)/s, 2.0));
+
   return val;
 }
 
@@ -29,11 +41,16 @@ void skewedGaussian()
   FILE *fp;
   char fln[256];
 
-  const Double_t B0 = 100.0; // (G)
-  const Double_t sm = 4.0;   // (G)
-  const Double_t sp = 5.0;  // (G)
+  const Double_t w  = 1.0;   // weight of the skewed Gaussian
+  const Double_t B0 = 100.0; // skewed Gaussian B0 (G)
+  const Double_t sm = 4.5;   // skewed Gaussian sigma- (G)
+  const Double_t sp = 4.5;  // skewed Gaussian sigma+ (G)
 
-  sprintf(fln, "skewedGauss-B%0.2lf-sm%0.2lf-sp%0.2lf.dat", B0, sm, sp);
+  const Double_t B0ext = 110.0; // external field Gaussian B0 (G)
+  const Double_t sext  = 1.2;   // external field Gaussian sigma (G)
+
+  sprintf(fln, "skewedGauss-B%0.2lf-sm%0.2lf-sp%0.2lf-w%0.1lf-Bext%0.2lf-sext%0.2lf.dat",
+          B0, sm, sp, w, B0ext, sext);
 
   const Int_t noOfPoints = 1000;
 
@@ -41,14 +58,15 @@ void skewedGaussian()
 
   fp = fopen(fln, "w");
 
-  fprintf(fp, "# title: skewed Gaussian\n");
-  fprintf(fp, "# parameter: B0 = %lf, sm = %lf, sp = %lf\n", B0, sm, sp);
+  fprintf(fp, "# title: skewed Gaussian + background\n");
+  fprintf(fp, "# parameter: B0 = %lf, sm = %lf, sp = %lf, w = %lf\n", B0, sm, sp, w);
+  fprintf(fp, "#            B0ext = %lf, sext = %lf, \n", B0ext, sext);
   fprintf(fp, "# -----------------------------------------------------\n");
   fprintf(fp, "# B, pB\n");
   Double_t b, pb;
   for (Int_t i=0; i<noOfPoints; i++) {
     b  = B0-10.0*sm + res * i;
-    pb = PofB(b, B0, sm, sp);
+    pb = w*PofB(b, B0, sm, sp) + (1.0-w)*PofBext(b, B0ext, sext);
     fprintf(fp, "%lf, %lf\n", b, pb);
   }
   fprintf(fp, "# end of file\n");